Digital video system

ABSTRACT

The erasion level appending range of a file is instructed. According to this instruction, the erasion level is set. When this setting range does not agree with the cell unit of the current cell, the current cell is divided to set a sequence of divided cells. Playback management information of each of the divided cells and current cell is re-created, and erasion level information is appended to playback management information of the divided cell that belongs to the appending range.

CROSS REFERENCE TO RELATED APPLICATION

This Application is a Divisional of co-pending application Ser. No.10/417,214, filed on Apr. 17, 2003, which is a Divisional of applicationSer. No. 09/623,460, filed on Sep. 12, 2000, now granted as U.S. Pat.No. 6,580,872, which is the National Stage of International ApplicationNo. PCT/JP99/03668, filed on Jul. 7, 1999. This Application is basedupon and claims the benefit of priority from the prior PatentApplication No. 10-192064, filed in Japan on Jul. 7, 1998, the entirecontents of all of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a digital video system (apparatus andmethod) capable of real-time recording, and an information recordingmedium (recordable optical disc) used in this system.

BACKGROUND ART

In recent years, systems for playing back the contents of optical discssuch as video CDs that record video data, audio data, and the like havebeen developed, and have prevailed for the purpose of playing back moviesoftware titles, karaoke data, and the like.

Among such systems, a DVD (Digital Versatile Disc) standard that usesMPEG2 (Moving Picture Experts Group 2) international standards has beenproposed.

This standard supports MPEG2 as a moving picture compression scheme, andAC-3 audio, MPEG audio, and the like as audio schemes. The standard isappended with sub-picture data for superimposed dialogs and menusobtained by compressing bitmap data, and control data (navigation data)for special playback control. Furthermore, this standard supports theUDF (Universal Disc Format) Bridge (a hybrid of UDF and ISO9660) toallow a computer to read data.

Also, optical discs such as a DVD-RAM and the like on which digital datacan be written or rewritten have been developed. A function that allowsone to easily edit the recorded contents is required of a digital videosystem using such DVD-RAM or the like.

However, a home-use digital video system which allows end-users toeasily edit the recorded contents has not become available yet.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide a digital videosystem (apparatus and method) which allows easy and flexible editing.

It is another object of the present invention to provide an informationrecording medium (recordable optical disc) which allows efficient datamanagement, and can manage save units finely.

In order to achieve the above objects, the digital video system of thepresent invention uses a data area for storing file data containingdigital movie information recorded in a predetermined recording unit;and a management area for storing navigation data for managinginformation stored in the data area. In this system the management areaincludes a storage field for storing an erasion level flag which sets aspecific recording unit in the data area in a temporarily erased state.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view for explaining the structure of arecordable optical disc according to an embodiment of the presentinvention;

FIG. 2 is a view for explaining an example of the logical structure ofinformation recorded on the optical disc shown in FIG. 1;

FIG. 3 is a view for explaining an example of the directory structure ofinformation (data files) recorded on the optical disc shown in FIG. 1;

FIG. 4 is a view for explaining an example of the hierarchical structureof a video object set (VTS) shown in FIG. 2;

FIG. 5 is a view for explaining the contents of packs in the lowermostlayer of the hierarchical structure shown in FIG. 4;

FIG. 6 is a view for explaining the contents of presentation controlinformation (PCI) shown in FIG. 5;

FIG. 7 is a view for explaining the contents of presentation controlinformation general information (PCI_GI) shown in FIG. 6;

FIG. 8 is a view for explaining the contents of video title setinformation (VTSI) shown in FIG. 2;

FIG. 9 is a view for explaining the contents of a video title setprogram chain information table (VTS_PGCIT) shown in FIG. 8;

FIG. 10 is a view for explaining the contents of program chaininformation (PCGI) shown in FIG. 9;

FIG. 11 is a view for explaining the contents of a cell playbackinformation table (C_PBIT) shown in FIG. 10;

FIG. 12 is a view for explaining the contents of cell playbackinformation (C_PBI) shown in FIG. 11;

FIG. 13 is a view for explaining the contents of a cell category (C_CAT)shown in FIG. 12;

FIG. 14 is a view for explaining the contents of program chain generalinformation (PGC_GI) for normal PGC;

FIG. 15 is a view for explaining the contents of program chain generalinformation (PGC_GI) for trash PGC;

FIG. 16 is a view for explaining the contents of cell playbackinformation (C_PBI) for trash PGC;

FIG. 17 is a view for explaining the format of digital informationrecorded on the optical disc shown in FIG. 1;

FIG. 18 is a view for explaining the data structure of a video objectunit (VOB) shown in FIG. 17;

FIG. 19 is a view for explaining the data structure of a dummy packshown in FIG. 18;

FIG. 20 is a view for explaining the file structure of digitalinformation recorded on the optical disc shown in FIG. 1;

FIG. 21 is a view for explaining the data structure of a navigation datafile (RTR_VMG) shown in FIG. 20;

FIG. 22 is a view for explaining the contents of a video managerinformation table (VMGI_MAT) shown in FIG. 21;

FIG. 23 is a view for explaining the data structure of a movie AV fileinformation table (M_AVFIT) shown in FIG. 21;

FIG. 24 is a view for explaining the data structure of movie VOBinformation (M_VOBI) shown in FIG. 23;

FIG. 25 is a view for explaining the data structure of time mapinformation (TMAPI) shown in FIG. 24;

FIG. 26 is a view for explaining the data structure of a user definedPGC information table (UD_PGCIT) shown in FIG. 21;

FIG. 27 is a view for explaining the data structure of PGC information(PGCI; information of an original PGC or user defined PGC);

FIG. 28 is a view for explaining the contents of PGC general information(PGC_GI) shown in FIG. 27;

FIG. 29 is a view for explaining the contents of program information(PGI) shown in FIG. 27;

FIG. 30 is a view for explaining the data structure of cell information(CI) shown in FIG. 27;

FIG. 31 is a view for explaining the data structure of movie cellinformation (M_CI) shown in FIG. 30;

FIG. 32 is a view for explaining the contents of movie cell generalinformation (M_C_GI) shown in FIG. 31;

FIG. 33 is a view for explaining the contents of movie cell entry pointinformation (M_C_EPI) shown in FIG. 31;

FIG. 34 is a block diagram showing an example of the arrangement of anapparatus for recording/playing back a video program or the like in realtime (RTR video recorder) using the recordable optical disc shown inFIG. 1;

FIG. 35 is a flow chart for explaining recording in the apparatus shownin FIG. 34;

FIG. 36 is a flow chart for explaining an erasion level setup process;

FIG. 37 is a flow chart continued from FIG. 36;

FIG. 38 is a view for explaining examples of windows displayed uponsetting the erasion level;

FIG. 39 is a view for explaining cell division;

FIG. 40 is a flow chart for explaining recovery (restoration) and actualerasion of a cell in which an erasion level flag is set;

FIG. 41 is a view for explaining examples of windows displayed uponrecovering (restoring) and actually erasing a cell in which an erasionlevel flag is set;

FIG. 42 is a flow chart for explaining automatic erasion of a cell inwhich an erasion level flag is set;

FIG. 43 is a view for explaining example of windows displayed uponerasing a cell in which an erasion level flag is set;

FIG. 44 is a flow chart for explaining the playback process of theapparatus shown in FIG. 34;

FIGS. 45–48 are a set of flow charts explaining a manner of dividing VOBand cell;

FIG. 49 explains a manner of dividing cells where one cell is equal toone VOB; and

FIG. 50 explains a manner of dividing VOBs where one cell is not equalto one VOB.

BEST MODE OF CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will be describedhereinafter with reference to the accompanying drawings. In thisdescription, the same reference numerals and symbols denote illustratedcomponents having common functions throughout the figures, and arepetitive description thereof will be avoided.

FIG. 1 is a view for explaining the structure of a recordable opticaldisc according to an embodiment of the present invention. FIG. 1 alsoshows the correspondence between the data recording area of optical disc10 (DVD-RAM or the like), and data recording tracks recorded there.

The physical structure of the optical disc will be explained first.

Referring to FIG. 1, optical disc 10 has a structure obtained byadhering a pair of transparent substrates 14 each having recordablelayer 17 (one or two layers) using adhesive layer 20. Each substrate 14is formed of a 0.6-mm thick polycarbonate film, and adhesive layer 20consists of an ultraviolet setting resin having a thickness of 40 μm to70 μm. When the pair of substrates 14 are adhered to each other so thattheir recordable layers 17 contact each other on the surfaces ofadhesive layer 20, a 1.2-mm thick large-capacity optical disc 10 isobtained.

Reference numeral 22 denotes a center hole; and 24, a clamp area.Reference numeral 25 denotes an information area; 26, a lead-out area;27, a lead-in area; and 28, a data recording area. On recordable layer17 of information area 25, a recording track is continuously formed in,e.g., a spiral pattern. The continuous track is divided into a pluralityof physical sectors, which have serial numbers and are used as recordingunits.

Referring to FIG. 1, when disc 10 is a rewritable DVD-RAM/DVD-RW (orwrite once DVD-R), this disc is housed in a cartridge. When thecartridge that houses DVD-RAM disc 10 is loaded into a discrecording/playback apparatus (DVD video recorder or DVD video player),and is extracted, disc 10 alone remains in the apparatus.

The data recording track of recordable layer 17 is divided into aplurality of logical sectors (minimum recording units) each having agiven storage capacity, and data are recorded with reference to theselogical sectors. The recording capacity per logical sector is determinedto be 2,048 bytes which are equal to one pack data length.

FIG. 2 is a view for explaining an example of the logical structure ofinformation recorded on the optical disc shown in FIG. 1.

Information area 25 shown in FIG. 1 can have a structure shown in, e.g.,FIG. 2. The logical format of this structure is defined to comply with,e.g., the Universal Disc Format (UDF) Bridge (a hybrid of UDF andISO9660) as one of standard formats.

Referring to FIG. 2, data recording area 28 is assigned as a volumespace. Volume space 28 includes space (volume/file structure) 70 forinformation of the volume and file structures, space (DVD video area) 71for applications compatible with the DVD specifications, and space(other recording area) 73 for applications compatible withspecifications other than the DVD specifications.

Volume space 28 is physically divided into a large number of sectors,which have serial numbers. The logical addresses of data recorded onthis volume space 28 mean logical sector numbers, as specified by theUDF Bridge. The logical sector size in this space is 2,048 bytes as inthe physical sector size. The logical sector numbers are assigned serialnumbers in ascending order of physical sector number. Note that eachphysical sector is appended with error correction information and thelike unlike logical sectors.

Volume space 28 has a hierarchical structure, which includes volume/filestructure area 70, DVD video area 71 consisting of one or more videotitle sets VTS#n 72, and other recording area 73. These areas are splitup on the boundaries of logical sectors. Note that one logical sector isdefined to be 2,048 bytes, and one logical block is also defined to be2,048 bytes. Hence, one logical sector is defined equivalently with onelogical block.

Volume/file structure area 70 corresponds to a management area definedby the UDF Bridge. Based on the description of this area 70, thecontents of video manager VMG are stored in an internal system memory(not shown) of the apparatus.

DVD video area 71 is constructed by file 74A containing one or morevideo title sets VTS 72, and video manager VMG for managing these VTS.Note that VMG contains video manager information VMGI, video object setVMGM_VOBS for manager menus, and backup file VMGI_BUP of VMGI, asneeded.

Each VTS 72 is constructed by file 74B that contains video object setVTSM_VOBS for video title set menus, video object set VTSTT_VOBS forvideo title set titles, video title set information VTSI for managingVTSTT_VOBS, and backup file VTSI_BUP of VTSI, as needed.

Other recording area 73 can record information that can be used in VTSmentioned above or other kinds of information that are irrelevant toVTS.

Note that VTSTT_VOBS defines a set of one or more video objects VOB.Each VOB defines a set of one or more cells. A set of one or more cellsmake up program chain PGC. Assuming that one PGC corresponds to onedrama, a plurality of cells that make up this PGC can correspond tovarious scenes in that drama.

When volume space 28 of single disc 10 stores a plurality of video titlesets VTS#n, the structure shown in FIG. 2 is suitably used. However,when volume space 28 of single disc 10 stores only one video title setVTS, another structure may be used. An example of such structure will bedescribed later with reference to FIG. 17. In this structure, file 74Ashown in FIG. 2 is omitted, and a file similar to file 74B is stored inthe data area of DVD video area 71 instead.

FIG. 3 shows an example of the directory structure of information (datafiles) recorded on optical disc 10.

As shown in FIG. 3, the subdirectory of video title set VTS, that ofaudio title set ATS, and the like are linked under the root directory.Various video files (files VMGI, VMGM, VTSI, VTSM, VTS, and the like)are contained in the subdirectory of VTS and managed systematically. Aspecific file (e.g., specific VTS) can be accessed by designating thepath from the root directory to that file.

DVD-RAM (DVD-RW) disc 10 or DVD-R disc 10 may be pre-formatted to havethe directory structure shown in FIG. 3 (or FIG. 20 to be describedlater), and pre-formatted discs 10 may be put on the market as unuseddiscs (raw discs) for DVD video recording.

That is, the root directory of pre-formatted raw disc 10 includes asubdirectory named VTS (or DVD_RTR shown in FIG. 20). This subdirectorycan contain various management data files (VIDEO_TS.IFO, VTS_01_0.IFOshown in FIG. 3; RTR.IFO shown in FIG. 20); backup files (VIDEO_TS.BUP,VTS_01_0.BUP; backup files are omitted in FIG. 20) for backing upinformation of these management data files; and video data files(VTS_01_1.VOB and the like in FIG. 3; RTR_MOV.VRO and the like in FIG.20) which are managed based on the contents of the management data filesand store digital moving picture information.

The subdirectory (VTS directory in FIG. 3 or DVD_RTR directory in FIG.20) can also contain menu data files (VMGM, VTSM) for storingpredetermined menu information, as needed.

On single disc 10, a file called video manager VMG is present asinformation (navigation data) for managing this disc. Furthermore, titleset VTS contains a video title set information VTSI file (RTR.IFO incase of FIG. 20), video file, and backup file of VTSI.

FIG. 4 shows the hierarchical structure of information contained invideo title set title video object set VTSTT_VOBS.

As shown in FIG. 4, video object set VTSTT_VOBS 82 is defined as a setof one or more video objects VOB 83. Each VOB 83 is made up of a set ofone or more cells 84, each of which is, in turn, made up of a set of oneor more video object units VOBU 85. Each VOBU is made up of a set ofvarious data packs 86 to 91.

Each of these packs serves as a minimum unit of data transfer. Theminimum unit for logical processing is a cell, and logical processing isdone is units of cells. (When the data structure shown in FIGS. 20 to 33to be described later is used, processing which uses entry points thatcan be units smaller than cells can be done.)

The playback time of VOBU corresponds to that of video data made up ofone or more picture groups (groups of pictures GOP in MPEG), and is setto fall within the range from 0.4 sec to 1.2 sec. One GOP is screen datawhich normally has a playback time of about 0.5 sec in the MPEG format,and is compressed to play back approximately 15 images during thisinterval. Note that even playback data consisting of audio data and/orsub-picture data alone is formed using VOBU as one unit.

When a DVD video recorder can record VOBS with this structure(RTR_MOV.VRO in FIG. 20) on optical disc 10, the user often wants toedit the recording contents after recording. In order to meet suchrequirement, dummy packs can be appropriately inserted in each VOBU.Each dummy pack can be used to record edit data later.

VOBS for menus normally consists of one VOB, which stores a plurality ofmenu screen display data. By contrast, VOBS for title sets normallyconsists of a plurality of VOBs.

VOB is assigned an identification number (IDN#i; i=0 to i), and that VOBcan be specified by the identification number. A normal video streamconsists of a plurality of cells, but a menu video stream often consistsof a single cell. Each cell is assigned an identification number(C_IDN#j) as in VOB.

As mentioned above, the video file (file 74A or 74B in FIG. 2) has ahierarchical structure, and one file is constructed by one or moreprogram chains PGC, each of which is, in turn, constructed by one ormore programs. One program is constructed by one or more cells, each ofwhich is, in turn, constructed by one or more video object units VOBU.Each VOBU is constructed by packs each containing a plurality of kindsof data, and each pack is constructed by one or more packets and a packheader.

Video object VOB corresponds to management data PGCI in units of PCGs(this PGCI corresponds to ORG_PGCI in FIG. 21 or UD_PGCI in FIG. 26 tobe described later). PGCI stores cell playback information table C_PBITfor managing cells, which are played back in the order described inC_PBIT. Actual cell playback addresses are recorded as cell playbackinformation C_PBI (which corresponds to CI in FIG. 27 to be describedlater) in C_PBIT.

In the embodiment of the present invention, management information forPGC and that for cells can be independent from each other.

FIG. 5 shows an example of the contents of packs in the lowermost layerof the hierarchical structure shown in FIG. 4. This pack sequenceincludes navigation pack 86, video packs 88, dummy packs 89, sub-picturepacks 90, audio packs 91, and the like.

Navigation pack 86 includes pack header 110, playback controlinformation/presentation control information (PCI) packet 116, and datasearch information (DSI) packet 117. PCI packet 116 is made up of packetheader 112 and PCI data 113, and DSI packet 117 of packet header 114 andDSI data 115.

PCI packet 116 contains control data used upon, e.g., non-seamlesslyswitching the playback angles. DSI packet 117 contains control data usedupon, e.g., seamlessly switching the playback angles. Note that the“angle switching” means changes in angle (camera angle) in which theobject picture is watched.

When the structure shown in FIGS. 17 and 18 to be described later isused, navigation pack 86 is not used, and navigation data RTR_VMG shownin FIG. 20 is used instead.

Video pack 88 is comprised of pack header 881 and video packet 882. Thedummy pack is comprised of pack header 891 and padding packet 890, andpadding packet 890 of packet header 892 and padding data 893. Note thatpadding data 893 stores insignificant data.

Sub-picture pack 90 is made up of pack header 901 and sub-picture packet902. The audio pack is made up of pack header 911 and audio packet 912.

Note that video packet 882 contains a packet header (not shown), whichrecords a decode time stamp (DST) and presentation time stamp (PTS).Each of sub-picture packet 902 and audio packet 912 contains a packetheader (not shown), which records a presentation time stamp (PTS).

FIG. 6 shows the contents of the presentation control information (PCIdata 113) shown in FIG. 5.

The PCI data includes PCI general information (PCI_GI), non-seamlessplayback angle information (NSML_AGLI), highlight information (HLI), andrecording information (RECI). This recording information (RECI) cancontain a copyright management code (ISRC) of the internationalstandard.

FIG. 7 shows the contents of the presentation control informationgeneral information (PCI_GI) shown in FIG. 6.

Presentation control information general information PCI_GI describesthe logical block number (NV_PCK_LBN) of a navigation pack, the category(VOBU_CAT) of VOBU, user operation control (VOBU_UOP_CTL) of VOBU, thestart presentation time (VOBU_S_PTM) of VOBU, the end presentation time(VOBU_E_PTM) of VOBU, the end presentation time (VOBU_SE_PTM) of thesequence end in VOBU, and a cell elapse time (C_ELTM).

Note that the logical block number (NV_PCK_LBN) represents the address(recording location) of a navigation pack including the presentationcontrol information (PCI) by the relative number of blocks from thefirst logical block in the video object set (VOBS) which includes thatPCI.

VOBU_CAT describes the contents of copy protection of an analog signalcorresponding to video and sub-picture data in VOBU that includes thepresentation control information (PCI). VOBU_UOP_CTL describes useroperations which are prohibited during the display (presentation) periodof VOBU that includes the presentation control information (PCI).VOBU_S_PTM describes the start time of display (presentation) of VOBUthat includes the presentation control information (PCI). Morespecifically, this VOBU_S_PTM indicates the start display time of thefirst video (first picture) in the display order of the first GOP inVOBU.

VOBU_E_PTM describes the end time of display (presentation) of VOBU thatincludes the presentation control information (PCI). More specifically,this VOBU_E_PTM indicates the end display time of the last video (lastpicture) in the display order of the last GOP in VOBU.

On the other hand, when no video data is present in VOBU, or whenplayback of that VOBU is stopped, this VOBU_E_PTM indicates the end timeof virtual video data aligned to time grids of field intervals ( 1/60sec in case of NTSC video).

VOBU_SE_PTM describes the end time of display (presentation) based on asequence end code in video data in VOBU that includes the presentationcontrol information (PCI). More specifically, this end time indicatesthe end display time of the last video (last picture) in the displayorder, which picture includes the sequence end code, in VOBU. If novideo (picture) with a sequence end code is present in VOBU, 00000000h(h is an abbreviation for hexadecimal) is set in VOBU_SE_PTM.

C_ELTM describes the relative display (presentation) time from the firstvideo frame in the display order of a cell that includes thepresentation control information (PCI) to the first video frame in thedisplay order of VOBU that includes the PCI in hours, minutes, andseconds in the BCD format and frames. When no video data is present inVOBU, the first video frame of the virtual video data is used as thevideo frame.

FIG. 8 shows the contents of the video title set information (VTSI)shown in FIG. 2.

This VTS consists of a plurality of files. Each file contains videotitle set information (VTSI), object set (VTSM_VOBS) for video title setmenus, video object sets (VTSTT_VOBS) for video title set titles, andbackup information (VTSI_BUP) for video title set information.

VTSI set at the beginning of VTS describes a video title set informationmanagement table (VTSI_MAT), a title search pointer table (VTS_PTT_SRPT)for a VTS part_of_title (e.g., chapter of a program), a VTS programchain information table (VTS_PGCIT), a VTS menu PGC information unittable (VTSM_PGCI_UT), a VTS time map table (VTS_TMAPT), a VTS menu celladdress table (VTSM_C_ADT), a VTS menu VOBU address map(VTSM_VOBU_ADMAP), a VTS cell address table (VTS_C_ADT), and a VTS VOBUaddress map (VTS_VOBU_ADMAP) in this order.

The contents of video title set information management table VTSI_MAT(corresponding to VMGI_MAT shown in FIG. 22 to be described later) areas follows.

More specifically, VTSI_MAT describes a VTS identifier, the end addressof VTS, a played back flag indicating whether or not a program recordedon optical disc 10 has been completely played back at least once, anarchive flag (ARCHIVE_FLAG; this flag may be omitted, and replaced by aflag in units of cells, as will be described later) which serves toprevent erase errors when a program recorded on optical disc 10 is to bekept without being erased, the end address of VTSI, the format that thisoptical disc 10 uses and its version number, a VTS category, the endaddress of VTSI_MAT, the start address of VTS menu VOBS, and the startaddress of VTSTT_VOBS.

Furthermore, VTSI_MAT describes the start address (VTS_PTT_SRPT_SA) ofthe part_of_title search pointer table to allow a search for part ofVTS, the start address. (VTS_PGCIT_SA) of the PGC information table thatsets the playback order of VTS, the start address (VTSM_PGCI_UT_SA) ofthe PGC information unit table for VTS menu display control, the startaddress (VTS_TMAST_SA) of the time map table indicating the elapse timeof VTS, the start address (VTSM_C_ADT_SA) of the cell address table ofcells used for VTS menu display, the start address (VTSM_VOBU_ADMAP_SA)of the VOBU address map for VTS menu display, the start address(VTS_C_ADT_SA) of the VTS cell address table, the start address(VTS_VOBU_ADMAP_SA) of the VTS VOBU address map, information ofattributes of video data, audio data, sub-picture data, and the like,the number of sub-picture streams of VTS, a sub-picture stream attributetable of VTS, and a multichannel audio stream attribute table of VTS.

FIG. 9 shows the contents of the video title set program chaininformation table (VTS_PGCIT) shown in FIG. 8.

This VTS_PGCIT contains VTS program chain information table information(VTS_PGCITI), VTS program chain information search pointers(VTS_PGCI_SRP#1 to VTS_PGCI_SRP#n), and VTS program chain information(VTS_PGCI).

Note that the order of a plurality of pieces of information VTS_PGCI isset independently of that of the plurality of VTS program chaininformation search pointers VTS_PGCI_SRP#1 to VTS_PGCI_SRP#n. Hence, forexample, single program chain information VTS_PGCI can be indicated byone or more program chain information search pointers VTS_PGCI_SRP.

FIG. 10 shows the contents of the program chain information (PGCI) shownin FIG. 9.

PGCI is made up of PGC general information (PGC_GI), a PGC command table(PGC_CMDT), a PGC program map (PGC_PGMAP), cell playback informationtable (C_PBIT), and cell position information table (C_POSIT).

FIG. 11 shows the contents of the cell playback information table(C_PBIT) shown in FIG. 10.

This cell playback information table C_PBIT can contain a maximum of 255pieces of cell playback information (C_PBIn; #n=#1 to #255).

Note that cell playback information C_PBI used in the structure shown inFIG. 2 corresponds to cell information CI (FIGS. 27 and 30) used in thestructure shown in FIG. 17 (to be described later).

FIG. 12 shows the contents of cell playback information C_PBI (C_PBI#1to C_PBI#n) shown in FIG. 11.

More specifically, each C_PBI contains a cell category (C_CAT), cellplayback time (C_PBTM), the start address (C_FVOBU_SA) of the firstvideo object unit (VOBU) in the cell, the end address (C_FILVU_EA) ofthe first interleaved unit (ILVU) in the cell, the start address(C_LVOBU_SA) of the last VOBU in the cell, and the end address(C_LVOBU_EA) of the last VOBU in the cell.

Furthermore, in this C_PBI, a 1-byte field (cell type) for describing anerasion level flag is assured.

When this erasion level flag is 00h, a cell appended with this flag canbe played back (or not set in an erasion state), and this flag can beused to mean prohibition of automatic erasion.

When the erasion level flag is 01h, a cell appended with this flag isprohibited from being played back (or set in an erasion state), and thisflag can be used to mean permission of automatic erasion.

The contents corresponding to the cell erasion level flag shown in FIG.12 can be described in primary text information PRM_TXTI shown in FIG.33 (to be described later).

FIG. 13 shows the contents of the cell category (C_CAT) shown in FIG.12.

This C_CAT indicates the number of cell commands by the lower 8 bits;the cell still time by the next 8 bits (b8 to b15); the cell type withcontents different from that shown in FIG. 12 by the next 5 bits; anaccess restriction flag by the next 1 bit; the cell playback mode (e.g.,movie or still) by the next 1 bit; a seamless angle change flag by 1 bitafter the next reserved bit; a system time clock STC discontinuity flag(to reset STC or not) by the next 1 bit; an interleaved allocation flag(indicating if the cell designated by C_PBI is located in a continuousblock or an interleaved block) by the next 1 bit; a seamless playbackflag (indicating if the cell designated by C_PBI is to be played backseamlessly) by the next 1 bit; the cell block type (e.g., angle block)by the next two bits; and the cell block mode (e.g., first cell in theblock) by the last two bits.

If the cell block mode bits are 00b (b means binary), this means thatthe cell is not the one in the block; if the bits are 01b, the cell isthe first one in the block; if the bits are 10b, the cell is the one inthe block; and if the bits are 11b , the cell is the last one in theblock.

If the cell block type bits are 00b, this indicates that the cell blockdoes not belong to the corresponding block; and if the bits are 01b, thecorresponding block is an angle block (a block containing multianglecells).

On the other hand, if this cell block type=01b is detected duringplayback, the apparatus can inform the viewer that playback of the angleblock is currently in progress by flickering an angle mark (or bychanging the ON color or shape of the angle mark). With suchinformation, the viewer can make sure that an image in another angle isavailable for the picture which is currently being played back.

If the interleaved allocation flag is 0b, it indicates that thecorresponding cell belongs to a continuous block (that continuouslyrecords a plurality of VOBUS); if the interleaved allocation flag is 1b,the corresponding cell belongs to an interleaved block (thatinterleaved-records ILVUs each containing one or more VOBUS).

If the seamless angle change flag is set (=1b), it represents that thecorresponding cell is to be seamlessly played back; if this flag is notset (=0b), the corresponding cell is to be non-seamlessly played back.

That is, if the interleaved allocation flag=1b and seamless angle changeflag=0b, the angle can be changed non-seamlessly; if the interleavedallocation flag=1b and seamless angle change flag=1b, the angle can bechanged seamlessly.

If a media drive system with a very short access time (a system that canaccess the beginning of a desired angle block within one video frameperiod; not limited to an optical disc drive system) is used, the anglecan be changed smoothly even when the interleaved allocation flag=0b,i.e., between VOBU sets (different angle cells) which are notinterleaved-recorded.

When optical disc 10 with relatively low access speed is used as arecording medium, one recording track of that disc is preferablyassigned to recording of one interleaved block. In such format, sincethe trace destination of an optical head need only move in the radialdirection of the disc by a very small distance corresponding to onetrack width, track jump suffering less time lag (suitable for seamlessangle change) can be attained. In this case, if track jump for one videoobject unit (VOBU) is made, a time lag for a maximum of one revolutionof the disc may be produced. Hence, the angle change that requires jumpsin units of VOBUs is suitable for non-seamless angle change.

It is technically possible to design a DVD video recorder which allowsthe viewer (user) to arbitrarily change the contents of the seamlessangle change flag in read data after cell data of the correspondingtitle set are read from an optical disc.

When the seamless angle change flag represents whether the angleinformation described in navigation pack 86 indicates seamless ornon-seamless angle information, if the user has changed this flag, he orshe must also modify angle information (not shown) in navigation pack 86(e.g., modification from seamless angle information to non-seamlessangle information).

When the cell playback mode is 0b, it indicates continuous playback inthe cell; if the mode is 1b, still playback in each VOBU present in thecell.

The access restriction flag can be used to prohibit direct selection byuser operation when the user makes recording, playback, and the like.For example, when the access restriction flag of a cell that recordsanswers for a collection of questions is set (=1b ), the user isprohibited from reading the answers by stealth.

The cell type in FIG. 13 with contents different from those of the celltype shown in FIG. 12 can indicate the following facts by its 5-bitcontents, for example, when the corresponding cell is formed forkaraoke.

If the 5 bits are 00000b, no cell type is designated; if the 5 bits are00001b, a title picture of the karaoke is designated; if the 5 bits are00010b, an introduction part of the karaoke is designated; if the 5 bitsare 00011b, a song part other than a climax (bridge) part is designated;if the 5 bits are 0010b, a song part of the first climax part isdesignated; if the 5 bits are 00101b, a song part of the second climaxpart is designated; if the 5 bits are 00110b, a song part for a malevocal is designated; if the 5 bits are 00111b, a song part for a femalevocal is designated; if the 5 bits are 01000b, a song part for mixedvoices is designated; if the 5 bits are 01001b, an interlude part(instrumental part) is designated; if the 5 bits are 01010b, fading-inof the interlude part is designated; if the 5 bits are 01011b,fading-out of the interlude part is designated; if the 5 bits are01100b, the first ending part is designated; and if the 5 bits are01101b, the second ending part is designated. The contents of theremaining 5-bit code can be used for other purposes.

Note that the angle change can be applied to that for background videodata of the karaoke. (For example, a full-figure shot, closeup shots ofthe face and mouth, and the like of a singer who is singing a guidevocal can be angle-changed seamlessly along with the flow of a karaokemusic or non-seamlessly by going back some bars, or during repeatplayback between desired bars, whichever the viewer desires.)

On the other hand, if the 8-bit contents of the cell still time are00000000b, zero still time is designated; if the contents are 11111111b,limitless still time is designated; if the contents fall within therange from 00000001b to 11111110b, a still display time having aduration defined by the decimal value (1 to 254) designated by thecontents and expressed in seconds is designated. The number of cellcommands indicates the number of commands to be executed upon completionof playback of the corresponding cell.

FIG. 14 shows the contents of general information (PGC_GI) of a normalprogram chain (PGC).

More specifically, program chain general information PGC_GI describesPGC contents (PGC_CNT), a PGC playback time (PGC_PB_TM), PGC useroperation control information (PGC_UOP_CTL), a PGC audio stream controltable (PGC_AST_CTLT), a PGC sub-picture stream control table(PGC_SPST_CTLT), PGC navigation control information (PGC_NV_CTL), a PGCsub-picture palette (PGC_SP_PLT), the start address (PGC_CMDT_SA) of aPGC command table, the start address (PGC_PGMAP_SA) of a PGC programmap, the start address (C_PBIT_SA) of a playback information table ofcells in PGC, and the start address (C_POSIT_SA) of a positioninformation table of cells in PGC.

PGC_CNT indicates the number of programs and number of cells (a maximumof 255) in that PGC. In PGC having no video object VOB, the number ofprograms is “0”.

PGC_PB_TM represents the total playback time of programs in that PGC inhours, minutes, seconds, and the number of video frames. This PGC_PB_TMalso describes a flag (tc_flag) indicating the type of video frame, anda frame rate (25 or 30 frames per sec) or the like is designated by thecontents of this flag.

PGC_UOP_CTL indicates user operations prohibited in PGC which is beingplayed back.

PGC_AST_CTLT can contain control information for each of eight audiostreams. Each control information includes a flag (availability flag)indicating if the corresponding audio stream is available in that PGC,and conversion information from an audio stream number to the number ofan audio stream to be decoded.

PGC_SPST_CTLT includes a flag (availability flag) indicating if thatsub-picture stream is available in the corresponding PGC, and conversioninformation from a sub-picture stream number (32 numbers) into thenumber of a sub-picture stream to be decoded.

PGC_NV_CTL includes Next_PGCN indicating the number of PGC to be playedback next after the PGC which is currently being played back,Previous_PGCN indicating the number (PGCN) of PGC quoted by a navigationcommand “LinkPrevPGC” or “PrevPGC_Search( )”, GoUp_PGCN indicating thenumber of PGC to which that PGC is to return, a PG Playback modeindicating the playback mode (sequential playback, random playback,shuffle playback, and the like) of the program, and a Still time valueindicating the still time after that PGC is played back.

PGC_SP_PLT describes 16 sets of luminance signals and two colordifference signals used in a sub-picture stream in that PGC.

PGC_CMDT_SA assures a description area for a pre-command executed beforePGC playback, a post-command executed after PGC playback, and a cellcommand executed after cell playback.

PGC_PGMAP_SA describes the start address of PGC_PGMAP representing theprogram configuration in that PGC by a relative address from the firstbyte of program chain information PGCI.

C_PBIT_SA describes the start address of cell playback information tableC_PBIT that determines the playback order of cells in that PGC by arelative address from the first byte of PGCI.

C_POSIT_SA describes the start address of cell position informationtable C_POSIT indicating VOB identification numbers and cellidentification numbers used in that PGC by a relative address from thefirst byte of PGCI.

FIG. 15 shows the contents of program chain general information (PGC_GI)of trash PGC that provides a “trash box” file for file erasion, and thelike.

Trash PGC_GI shown in FIG. 15 is configured by adding a trash PGC flag(TRASH_PGC_FLG) to PGC_GI shown in FIG. 14.

If this trash PGC flag is 01h, it indicates that the corresponding PGCis “trash PGC that pertains to playback of an erased cell”. On the otherhand, if this trash PGC flag is 00h , it indicates that thecorresponding PGC is not “trash PGC” but a normal PGC.

Trash PGC_GI shown in FIG. 15 is PGC general information when PGC isbuilt to permit playback of a cell, which is seemingly deleted(recording data remains undeleted in practice, but is prohibited frombeing played back by the erasion level flag), by inputting a specialkeyword (or by, e.g., mouse operation for dragging a file icon from atrash box icon).

In this case, the special keyword input for a specific cell in PGC withthe trash PGC flag=01h (i.e., “trash box”) corresponds to operation forrestoring a video file (file icon) that has been thrown into the “trashbox” file (trash icon) from the trash box.

FIG. 16 is a view for explaining the contents of cell playbackinformation (C_PBI) in trash PGC.

C_PBI of trash PGC shown in FIG. 16 has a configuration in which thecell type in C_PBI shown in FIG. 12 is replaced by PGC_N that designatesan original PGC number to which a cell that has been thrown into thetrash box belongs, and C_IN_N for designating that cell number.

This C_PBI of trash PGC has no “erasion level flag” shown in FIG. 12.

Cell playback information C_PBI shown in FIG. 16 is used for restoring a“cell which is seemingly deleted” that belongs to PGC with the trash PGCflag=01h in FIG. 15.

Management information (PGC_G₁ and C_PBI for trash PGC) for restoringand playing back a “cell thrown into the trash box” shown in FIGS. 15and 16 may be left in the internal memory of the apparatus (DVD videorecorder) or may be written on disc 10 as hidden information which isinvisible to the user.

FIG. 17 is a view for explaining the format of digital informationrecorded on the optical disc shown in FIG. 1.

In this structure, lead-in area 27 includes an emboss data zone whoselight reflection surface has an embossed pattern, a mirror zone whosesurface is flat (mirror surface), and a rewritable zone capable ofinformation rewriting. Lead-out area 26 is also designed to be capableof information rewriting.

Data recording area (volume space) 28 is made up of volume/filemanagement (structure) information 70 and data area DA whose contentscan be rewritten by the user.

Volume/file management information 70 records file information of audioand video data recorded on data area DA, and information that pertainsto the whole volume.

Data area DA can randomly record areas DA1 and DA3 for recordingcomputer data, and video & audio data area DA2 for recording video/audiodata. Note that the recording order, recording information size, and thelike of computer data and video/audio data can be arbitrarilydetermined. Data area DA can record computer data or video/audio dataalone.

Video & audio data area DA2 contains control information DA21, videoobject DA22, picture object DA23, and audio object DA24.

Control information DA21 can contain control information required uponexecuting various processes such as recording (image and/or audiorecording), playback, editing, search, and the like.

For example, control information DA21 can contain file RTR.IFO ofnavigation data RTR_VMG shown in FIG. 20 (to be described later).

Video object DA22 can contain information of the contents of recordedvideo data.

Picture object DA23 can contain still picture information of stillpictures, slide pictures, and the like.

Audio object DA24 can contain information of the contents of recordedaudio data.

Note that video object DA22 is made up of video object set VOBS. ThisVOBS has contents corresponding to one or more program chains PGC#1 toPGC#k which respectively designate cell playback orders by differentmethods.

The emboss data zone of lead-in area 27 records the followinginformation in advance:

(1) the disk type such as a DVD-ROM, DVD-RAM (or DVD-RW), DVD-R, and thelike; the disk size such as 12 cm, 8 cm, and the like; the recordingdensity; and information that pertains to the entire information storagemedium such as physical sector numbers indicating the recordingstart/end positions, and the like;

(2) the recording power and recording pulse width; the erasion power;the playback power; information that pertains torecording/playback/erasion characteristics such as the linear velocityupon recording/erasion, and the like; and

(3) information that pertains to the manufacture of an individualinformation recording medium such as the manufacturing number, and thelike.

The rewritable zone of each of lead-in area 27 and lead-out area 28contains the following fields:

(4) a field for recording a unique disk name of each informationrecording medium;

(5) a test recording field (for confirming recording/erasionconditions); and

(6) a field for recording management information that pertains to adefective field in data area DA.

A DVD-RTR recorder/player (RTR video recorder or personal computer witha DVD-RAM drive) can record data in fields (4) to (6).

When disc 10 is set in a DVD-RTR recorder/player (RTR video recorder),information in lead-in area 27 is read. Lead-in area records apredetermined reference code and control data in ascending order ofsector number.

The reference code in lead-in area 27 consists of two error correctioncode blocks (ECC blocks). Each ECC block has 16 sectors. These two ECCblocks (32 sectors) are generated by appending scramble data. Uponplaying back the reference code appended with the scramble data, fileoperation or the like on the playback side is done to play back aspecific data symbol (e.g., 172) to assure the subsequent data readprecision.

Control data in lead-in area 27 is made up of 192 ECC blocks. In thiscontrol data field, the contents for 16 sectors in the respective blocksare repetitively recorded 192 times.

This control data consisting of 16 sectors contains physical formatinformation in the first sector (2,048 bytes), and disc manufacturinginformation and contents provider information in the subsequent sectors.

The physical format information contained in the control data has thefollowing contents.

That is, the first location describes the version of the DVDspecifications the recording information complies with.

The second location describes the size (12 cm, 8 cm, or the like) of therecording medium (optical disc 10) and minimum read rate. In case ofread-only DVD video, 2.52 Mbps, 5.04 Mbps, and 10.08 Mbps are specifiedas minimum read rates, and other minimum read rates are reserved. Forexample, when image recording is done at an average bit rate of 2 Mbpsby an RTR video recorder capable of variable bit-rate recording, theminimum read rate can be set at 1.5 to 1.8 Mbps using the reservedfield.

The third location describes the disc structure (the number ofrecordable layers, track pitch, type of recordable layer, and the likeof the recording medium (optical disc 10). Based on the type ofrecordable layer, it can be identified if that disc 10 is a DVD-ROM,DVD-R, or DVD-RAM (DVD-RW).

The fourth location describes the recording density (linear density andtrack density) of the recording medium (optical disc 10). The lineardensity indicates the recording length per bit (0.267 μm/bit, 0.293μm/bit, or the like). The track density indicates the spacing betweenneighboring tracks (0.74 μm/track, 0.80 μm/track, or the like). Thefourth location includes a reserved field to designate other numericalvalues as linear and track densities for a DVD-RAM or DVD-R.

The fifth location describes the start and end sector numbers and thelike of data area 28 of the recording medium (optical disc 10).

The sixth location describes a burst cutting area (BCA) descriptor. ThisBCA is applied to only a DVD-ROM disc as an option, and is an area forstoring recording information after completion of the disc manufacturingprocess.

The seventh location describes a free space of the recording medium(optical disc 10). For example, when disc 10 is a single-sided,single-layered recording DVD-RAM disc, information indicating 2.6 GB (orthe number of sectors corresponding to this number of bytes) isdescribed at this location of disc 10. When disc 10 is a double-sidedrecording DVD-RAM disc, information indicating 5.2 GB (or the number ofsectors corresponding to this number of bytes) is described at thatlocation.

Other locations are reserved for future use.

FIG. 18 is a view for explaining the data structure of the video objectunit (VOB) shown in FIG. 17.

As shown in FIG. 18, each cell (e.g., cell #m) that forms video objectDA22 consists of one or more video object units (VOBU). Each VOBU isformed as a set (pack sequence) of video packs, sub-picture packs, audiopacks, dummy packs, and the like.

Each of these packs has a predetermined size, i.e., 2,048 bytes, andserves as a minimum unit upon transferring data.

The playback time of VOBU corresponds to that of video data made up ofone or more picture groups (GOP), and is set to fall within the rangefrom 0.4 sec to 1.2 sec. One GOP is screen data which normally has aplayback time of about 0.5 sec in the MPEG format, and is compressed toplay back approximately 15 images during this interval. (VOBU containsan integer number of GOPs, except for a special case wherein a gap isformed in the flow of video data. That is, VOBU is a video informationcompression unit synchronous with GOPs.)

When VOBU contains video data, a video data stream is formed by liningup GOPs (complying with the MPEG format) each consisting of video packs,sub-picture packs, audio packs, and the like. However, VOBU isdetermined with reference to the playback time of GOPs independently ofthe number of GOPs.

Note that even playback data consisting of audio data and/or sub-picturedata alone is formed using VOBU as one unit. For example, when VOBU isformed by audio packs alone, audio packs to be played back within theplayback time of the VOBU to which that audio data belongs are stored inthat VOBU like in a video object of video data.

The packs that form each VOBU have similar data structures except for adummy pack. An audio pack will be taken as an example. As shown in FIG.18, a pack header is allocated at the beginning of the pack, a packetheader and sub-stream ID follow, and audio data is allocated at the endof the pack. In such pack format, the packet header is written withinformation of presentation time stamp PTS indicating the start time ofthe first frame in the packet.

On the other hand, a video pack has a data structure obtained byexcluding the sub-stream ID from the audio pack shown in FIG. 18 (notethat the start video pack in VOBU has a predetermined system headerbetween the pack and packet headers).

In a DVD-RTR recorder/player that can record a video program thatcontains video object DA22 with the structure shown in FIG. 18 onoptical disc 10, the user often wants to edit the recording contentsafter recording. In order to meet such requirement, dummy packs can beappropriately inserted in each VOBU. Each dummy pack can be used torecord edit data later.

The dummy pack shown in FIG. 18 shows a data structure shown in FIG. 19.

More specifically, one dummy pack 89 is comprised of pack header 891,packet header 892 having a predetermined stream ID, and padding data 893padded with a predetermined code (insignificant data). Note that packetheader 892 and padding data 893 form padding packet 890. The contents ofpadding data 893 in a non-used dummy pack are not especiallysignificant.

This dummy pack 89 can be appropriately used when the recording contentsare to be edited after predetermined image recording is done on disc 10shown in FIG. 1, and in other cases (for example, the dummy pack is usedas an audio pack that stores audio information of after recording).

More specifically, the dummy pack is inserted into each VOBU for thepurposes of:

addition of information to be additionally recorded after imagerecording (for example, memo information indicating that after-recordinginformation is inserted into an audio pack and replaced by a dummy packis inserted as sub-picture information into a sub-picture pack and isreplaced by a dummy pack);

compensation of a short size from an integer multiple of 32 kbytes tomatch the VOBU size with an integer multiple of the ECC block size (32kbytes); and so forth.

Also, the dummy pack can be used to store reduced-scale image (thumbnailpicture) data which is displayed on a user menu, as needed.

FIG. 20 is a view for explaining an example of the directory structureof information (data files) recorded on the optical disc shown in FIG. 1to have the data structure shown in FIG. 17.

According to the DVD-RTR specifications capable of digitalrecording/playback of a video picture in real time, the contents of aDVD-RTR disc are managed using the directory structure shown in FIG. 20,and are saved in accordance with a file system such as ISO9660, UDF, orthe like. (RTR is an abbreviation for real time recording.)

Even when the data structure shown in FIG. 17 is used on thedisc/apparatus side, this data structure is invisible to the user. Thedata structure that the user can actually see is a hierarchical filestructure shown in FIG. 20.

More specifically, directories such as a DVD_RTR directory, VIDEO_TSdirectory, AUDIO_TS directory, computer data file directories, and thelike are displayed on the display screen (not shown) of the rootdirectory by means of menu windows, icons, or the like in correspondencewith the types of data recorded on data area DA shown in FIG. 17.

The DVD_RTR directory shown in FIG. 20 stores file RTR.IFO of navigationdata RTR_VMG, file RTR_MOV.VRO of movie video object RTR_MOV.VOB, fileRTR_STO.VRO of still picture video object RTR_STO.VOB, file RTR_STA.VROof additional audio object RTR_STA.VOB for still pictures, and the like.

Note that file RTR.IFO stores management information such as a programset, program, entry point, play list, and the like for managing movingpicture information.

File RTR_MOV.VRO stores recorded moving picture information and itsaudio information, file RTR_STO.VRO stores recorded still pictureinformation and its audio information, and file RTR_STA.VRO storesafter-recording data for a still picture, and the like.

When a DVD-RTR recorder/player (RTR video recorder) has a function ofdisplaying the directories shown in FIG. 20 and also has a playbackfunction of a DVD video disc (ROM disc), and the DVD video disc is setin its disc drive, the VIDEO_TS directory shown in FIG. 20 is activated.In this case, when the VIDEO_TS directory is opened, the recordingcontents of the set disc are further displayed.

When the DVD-RTR recorder/player has a DVD audio playback function and aDVD audio disc is set in its disc drive, the AUDIO_TS directory shown inFIG. 20 is activated. In this case, when the AUDIO_TS directory isopened, the recording contents of the set disc are further displayed.

Furthermore, when the DVD-RTR recorder/player comprises a personalcomputer with a DVD-RAM drive and has a computer data processingfunction, and a DVD-RAM (or DVD-ROM) disc that has recorded computerdata is set in that disc drive, the computer data directory shown inFIG. 20 is activated. In this case, when the computer data directory isopened, the recording contents of the set disc are further displayed.

The user can access the recorded sources of DVD video source, DVD videoROM, DVD audio, and computer data (including computer programs) as if heor she were operating a personal computer, while observing a menu screenor window display screen displayed with the directory structure shown inFIG. 20.

FIG. 21 is a view for explaining the data structure of the navigationdata file (RTR_VMG) shown in FIG. 20. RTR video manager RTR_VMG asnavigation data is comprised of various kinds of information, as shownin FIG. 21.

Referring to FIG. 21, RTR video manager information RTR_VMGI describesbasic information of recordable optical disc (RTR disc) 10 shown inFIG. 1. This RTR_VMGI contains video manager information managementtable VMGI_MAT and play list search pointer table PL_SRTP.

RTR_VMGI further contains movie AV file information table M_AVFIT, stillpicture AV file information table S_AVFIT, original PGC informationORG_PGCI, user defined PGC information table UD_PGCIT, text data managerTXTDT_MG, and manufacturer's information table MNFIT.

FIG. 22 shows the contents of the video manager information managementtable (VMGI_MAT) shown in FIG. 21.

Referring to FIG. 22, VMG identifier VMG_ID describes “DVD_RTR_VMG0”that specifies an RTR_VMG file using an ISO646 character set code.

RTR_VMG_EA describes the end address of RTR_VMG by a relative bytenumber from the first byte of RTR_VMG.

VMGI_EA describes the end address of RTR_VMGI by a relative byte numberfrom the first byte of RTR_VMG.

VERN describes the version number of the DVD specifications for videorecording (real time video recording).

TM_ZONE describes the time zone of the RTR disc. In the DVD_RTRspecifications, five different data fields (PL_CREATE_TM, VOB_REC_TM,FIRST_VOB_REC_TM, LAST_VOB_REC_TM, and VOBU_REC_TM) are specified. Thesefive different data fields are generally called REC_TM. REC_TM containsdata TZ_TY and TZ_OFFSET. TZ_TY describes a common universal time orlocal time, and TZ_OFFSET describes a date offset from the commonuniversal time in units of minutes.

STILL_TM describes the still time of a still picture in units ofseconds.

CHRS describes a character set code used in primary text information.With this CHRS, for example, an ISO8859-1 character set code or shiftJIS kanji code can be designated.

RSM_MRKI describes program chain number PGCN, program number PGN, cellnumber CN, marker point MRK_PT, and marker creation time MRK_TM. PGCN inthis information indicates the number of the program chain where amarker point is present. When the marker is present in an original PGC,PGCN is set at “0”. PGN indicates the number of the program where themarker point is present. When a resume marker is present in a userdefined PGC, PGN is set at “0”. CN indicates a marker point in a targetcell. When the resume marker is present in a movie cell, MRK_PTdescribes a presentation time (PTM) using an RTR presentation timedescription format. MRK_TM describes the time of creation of the markerusing an RTR date description format.

REP_PICTI describes program chain number PGCN, program number PGN, cellnumber CN, picture point PICT_PT, and representative picture creationtime CREAT_TM.

PGCN in this information indicates the number of the program chain wherea representative picture of the disc is present. The representativepicture of the disc is designated by only the pointer in an originalPGC. Hence, when this representative picture pointer is present, PGCN isset at “0”. PGN indicates the number of the program where therepresentative picture of the disc is present. When the resume marker ispresent in a user defined PGC, PGN is set at “0”. CN indicates thenumber of the cell where the representative picture of the disc ispresent. PICT_PT indicates the representative image of the disc in thetarget cell. When the representative picture is present in a movie cell,PICT_PT describes the presentation time (PTM) using the RTR presentationtime description format. When this representative image is present in astill picture cell, PICT_PT describes a still picture VOB entry number(S_VOB_ENTN) in a corresponding still picture VOB group (S_VOG).CREAT_TM describes the time of creation of the representative picture ofthe disc using the RTR date description format.

M_AVFIT_SA describes the start address of movie AV file informationtable M_AVFIT shown in FIG. 21 by a relative byte number from the firstbyte of RTR_VMG.

S_AVFIT_SA describes the start address of still picture AV fileinformation table S_AVFIT shown in FIG. 21 by a relative byte numberfrom the first byte of RTR_VMG.

ORG_PGCI_SA describes the start address of original PGC informationORG_PGCI shown in FIG. 21 by a relative byte number from the first byteof RTR_VMG.

UD_PGCIT_SA describes the start address of user defined PGC informationtable UD_PGCIT shown in FIG. 21 by a relative byte number from the firstbyte of RTR_VMG. If UD_PGCIT is not available, UD_PGCIT_SA is set at“0000 0000h”.

TXTDT_MG_SA describes the start address of text data manager TXTDT_MGshown in FIG. 21 by a relative byte number from the first byte ofRTR_VMG. If TXTDT_MG is not available, TXTDT_MG_SA is set at “00000000h”.

MNFIT_SA describes the start address of manufacturer's information tableMNFIT shown in FIG. 21 by a relative byte number from the first byte ofRTR_VMG. If MNFIT is not available, MNFIT_SA is set at “0000 0000h”.

FIG. 23 shows the data structure of the movie AF file information table(M_AVFIT) shown in FIG. 21.

M_AVFIT describes information of a movie AV file (file RTR_MOV.VRO shownin FIG. 20), and contains movie AV file information table informationM_AVFITI, one or more pieces of movie VOB stream information M_VOB_STI#1to M_VOB_STI#n, and movie AV file information M_AVFI.

M_AVFI is information of a movie AV file having a predetermined filename (RTR_MOV.VRO), and contains movie AV file information generalinformation M_AVFI_GI, one or more movie VOB information search pointersM_VOBI_SRP#1 to M_VOBI_SRP#n, and one or more pieces of movie VOBinformation M_VOBI#1 to M_VOBI#n.

One movie AV file can contain one or more VOBs, and each VOB has movieVOB information M_VOBI for VOB in M_AVFI. One or more pieces of M_VOBIin M_AVFI are described in the same order as that of VOB data stored inthe movie AV file.

FIG. 24 shows the data structure of the movie VOB information (M_VOBI)shown in FIG. 23. AS shown in FIG. 24, M_VOBI contains movie VOB generalinformation M_VOBI_GI, seamless information SMLI, audio gap informationAGAPI, and time information TMAPI.

M_VOBI_GI shown in FIG. 24 contains VOB_TY which describes the type ofVOB, VOB_REC_TM which describes the recording time of the start field inVOB using the RTR date description format, VOB_REC_TM_SUB whichdescribes the recording time (sub-second information) of the start fieldin VOB by the number of video fields, M_VOB_STIN which describes thenumber of movie VOB stream information, VOB_V_S_PTM which describes thepresentation start time of the first video field in VOB using the RTRpresentation time description format, and VOB_V_E_PTM which describesthe presentation end time of the last video field in the VOB using theRTR presentation time description format.

VOB_TY includes TE which indicates if that VOB has been temporarilyerased, A0_STATUS which indicates the status of audio stream #1, analogprotection system APS which indicates the format of analog copyprotection or the ON/OFF state of this copy protection, SML_FLG whichindicates if VOB is to be played back seamlessly, A0_GAP_LOC whichindicates if an audio gap is present in audio stream #0 and the locationof the audio gap if it is present, and A1_GAP_LOC which indicates if anaudio gap is present in audio stream #1 and the location of the audiogap if it is present.

VOB_REC_TM is updated to indicate the recording time of the start fieldof the remaining VOB if the start field of a given VOB is deleted(erased).

More specifically, “new VOB_REC_TM=old VOB_REC_TM+playback duration oferased field”.

On the other hand, if the playback duration of the erased field cannotbe displayed in units of seconds (for example, when the playbackduration of the erased field is 60.5 sec),

We have “new VOB_REC_TM+new VOB_REC_TM_SUB=old VOB_REC_TM+oldVOB_REC_TM_SUB+playback duration of erased field”.

Since VOB_REC_TM describes the date of video recording, even when audiodata has been modified, such modification has no influence onVOB_REC_TM.

The aforementioned RTR date description format will be briefly explainedbelow. In this format, playback time PTM is expressed by a PTM base andPTM extension. The PTM base is a value measured using 90 kHz as a unit,and the PTM extension is a value measured using 27 MHz as a unit.

SMLI shown in FIG. 24 contains VOB_FIRST_SCR which describes SCR (systemclock reference) of the first pack of current VOB using the RTRpresentation time description format, and PREV_VOB_LAST_SCR whichdescribes SCR of the last pack in previous VOB using the RTRpresentation time description format.

FIG. 25 shows the data structure of the time map information (TMAPI)shown in FIG. 24.

Time map information TMAPI is used upon executing special playback(e.g., cell playback in the order unique to each user using user definedPGC) and time search.

Time map information TMAPI includes time map generation informationTMAP_GI, one or more time entries TM-ENT#L to TM_ENT#r, and one or moreVOBU entries VOBU_ENT#1 to VOBU_ENT#q.

Each VOBU entry contains information of the size and playback time ofVOBU. The VOBU size is presented in units of sectors (2 kbytes), and theplayback time is presented in units of video fields (one field= 1/60 secin NTSC; one field= 1/50 sec in PAL).

Since the VOBU size is presented in units of sectors, as describedabove, VOBU can be accessed using addresses in units of sectors.

Each VOBU entry includes reference picture size information 1STREF_SZ,VOBU playback time information VOBU_PB_TM, and VOBU size informationVOBU_SZ.

Note that VOBU_PB_TM represents the playback time of VOBU of interest inunits of video fields. On the other hand, reference picture sizeinformation ISTREF_SZ represents the size of the first reference picture(corresponding to I-picture in MPEG) of VOBU of interest in units ofsectors.

On the other hand, each time entry contains address information(VOBU_ADR) of the corresponding VOBU, and time difference information(TM_DIFF). This time difference information indicates the differencebetween the playback time designated by the time entry and the VOBUpresentation start time.

Assuming that the time interval (time unit TMU) between two successivetime entries is 10 sec, this time entry interval corresponds to 600fields in, e.g., NTSC video.

Normally, the “time interval between neighboring VOBUs” is expressed bythe number of fields in the VOBU entry. As another method, “count valuefrom a given VOBU to the next VOBU by a clock counter” may be used toexpress the “time interval between neighboring VOBUs”.

For example, the “time interval between neighboring VOBUs” can beexpressed by the “difference value between the value of presentationtime stamp at the start position of one VOBU and the value of PTS at thestart position of the immediately succeeding VOBU”.

In other words, “the time interval in a specific unit can be expressedby the difference value of the clock counter in that unit”.

Time map generation information TMAP_GI shown in FIG. 25 includesTM_ENT_Ns indicating the number of time entries in that time mapinformation, VOBU_ENT_Ns indicating the number of VOBU entries in thattime map information, time offset TM_OSF for that time map information,and address offset ADR_OFS of that time map information.

When a value (10 seconds or equivalent) corresponding to 600 fields inNTSC video (or 500 fields in PAL video) is used as time unit TMU, timeoffset TM_OSF is used to represent the time offset within TMU.

When the VOBU size is expressed by the number of sectors, address offsetADR_OFS is used to indicate a file pointer from the beginning of an AVfile.

Time entry TM_ENT shown in FIG. 25 includes VOBU_ENTN indicating thenumber of the corresponding VOBU entry, TM_DIFF indicating the timedifference between the playback time of VOBU designated by the timeentry, and the calculated playback time, and VOBU_ADR indicating thetarget VOBU address.

When time unit TMU is expressed by 600 fields in NTSC (or when time unitTMU is expressed by 500 fields in PAL), the “calculated playback time”with respect to time entry #j is given by TMU×(j−1)+TM_OSF.

On the other hand, VOBU_ADR indicates the target VOBU address by thetotal size of VOBUs preceding VOBU of interest when the VOBU size isexpressed in units of sectors.

In the aforementioned data structure, in order to start playback fromthe middle of certain VOBU, that access point must be determined. Thisaccess point is assumed to be a time entry point.

This time entry point is located at a position separated from theposition indicated by movie address information of VOBU by the timedifference indicated by time difference information TM_DIFF in timeentry TM_ENT. This time entry point serves as a special presentationstart point (or time search point) indicated by time map informationTMAPI.

FIG. 26 shows the data structure of the user defined PGC informationtable (UD_PGCIT) shown in FIG. 21.

When a trash PGC is created, the trash PGC is defined as a part ofuser-defined PGC information (UD_PGCI). If no trash PGC is defined, agiven PGCN may be assigned to a trash PGC.

UD_PGCIT includes user defined PGC information table informationUD_PGCITI, one or more user defined PGCI search pointers UD_PGCI_SRP#1to UD_PGCI_SRP#n, one or more pieces of user defined PGC informationUD_PGCI#1 to UD_PGCI#n.

All UD_PGCs are assigned program chain numbers PGCN ranging from 1 to 99in the description order of UD_PGCI_SRP in UD_PGCIT. This PGCN canspecify each PGC.

UD_PGCITI contains UD_PGCI_SRP_Ns indicating the number of UD_PGCI_SRPs,and UD_PGCIT_EA indicating the end address of UD_PGCIT.

Note that the maximum value of UD_PGCI_SRP_Ns is set at, e.g., “99”.UD_PGCIT_EA represents the end address of UD_PGCIT by a relative bytenumber from the first byte of UD_PGCIT.

UD_PGCI_SRP includes start address UD_PGCI_SA of UD_PGCI. ThisUD_PGCI_SA represents the start address of UD_PGCI by a relative bytenumber from the first byte of UD_PGCIT.

FIG. 27 shows the data structure of the PGC information (PGCI). PGCIcontains navigation information for program chain PGC.

Two different types of program chains, i.e., original PGC and userdefined PGC, are available (see the contents of RTR_VMG shown in FIG.21). Original PGC has VOB and PGCI. However, user defined PGC does nothave its own VOB, and refers to VOB in original PGC.

As shown in FIG. 27, PGC information (PGCI#i) includes PGC generalinformation PGC_GI, one or more pieces of program information PGI#1 toPGI#m, one or more cell information search pointers CI_SRP#1 toCI_SRP#n, and one or more pieces of cell information CI#1 to CI#n.

Note that the start address of cell information CI can be indicated byCI_SA described as a relative byte number from the first byte of PGCI.

Here, PGCI of FIG. 27 corresponds to VTS_PGCI of FIG. 9, and thisVTS-PGCI corresponds to a combination of UD_PGCIF of FIG. 26 and anoriginal PGCI (ORG_PGCI).

FIG. 28 shows the contents of the PGC general information (PGC_GI) shownin FIG. 27.

This PGC_GI contains PG_Ns that describes the number of programs in PGC,and CI_SRP_Ns that describes the number of CI_SRPs in PGC.

In case of user defined PGC, PG_Ns is set at “0”. On the other hand, themaximum number of programs PG in original PGC is “99”, and the maximumnumber of cells in PGC is “999”.

This PGC_GI can also include a trash PGC flag as in PGC_GI of trash PGCshown in FIG. 15.

FIG. 29 shows the contents of the program information (PGI) shown inFIG. 27.

This PGI includes PG_TY which describes the type of program, C_Ns whichdescribes the number of cells in PG, primary text information PRM_TXTIused in PG, search pointer number IT_TXT_SRPTN of IT_TXT where text datacorresponds to PG, and thumbnail pointer information THM_PTRI.

Note that PRM_TXTI is constructed by a 128-byte field, and the first 64bytes of that field are described by an ASCII character set. When anASCII text is less than 64 bytes, “00h” is written in blank bytes.

The second 64 bytes of the 128-byte field are used to describe primarytext of another character set (e.g., shift JIS or ISO8859-15). Note thatthe code of “another character set” is described in VMGI_MAT, and isshared by all the pieces of primary text information in the disc.

Note that a terminal control code that assumes a value ranging from“01h” to “1Fh” is never described in PRM_TXTI.

THM_PTRI describes information of a thumbnail pointer. That is THM_PTRIincludes CN that describes the number of the cell where the thumbnailpointer is present, and THM_PT that describes the thumbnail pointer inthe target cell.

When the resume marker is present in a movie cell, THM_PT describes thepresentation time (PTM) using the RTR presentation time descriptionformat.

On the other hand, when a thumbnail is present in a still picture cell,THM_PT describes a still picture VOB entry number (S_VOB_ENTN) in acorresponding still picture VOB group (S_VOG).

THM_PTRI may be optionally set or used in either an RTR recorder orplayer. When the RTR recorder does not have performance capable ofprocessing THM_PTRI, all the pieces of 8-byte THM_PTRI may be set at“FFh”, On the other hand, when the RTR player does not have performancecapable of processing THM_PTRI, it may simply ignore THM_PTRI.

FIG. 30 shows the data structure of the cell information (CI) shown inFIG. 27.

As shown in FIG. 30, there are two kinds of cell information, i.e.,movie cell information M_CI and still picture cell information S_CI.

Information (M_C_EPI) that pertains to the entry point is written inmovie cell information M_CI in navigation data file RTR.IFO shown inFIG. 20.

FIG. 31 shows the data structure of the movie cell information (M_CI)shown in FIG. 30.

As shown in FIG. 31, M_CI contains movie cell general informationM_C_GI, and one or more pieces of movie cell entry point informationM_C_EPI#1 to M_C_EPI#n.

FIG. 32 shows the contents of the movie cell general information(M_C_GI) shown in FIG. 31.

That is, M_C_GI contains C_TY which describes the type of cell,M_VOBI_SRPN which describes the number of the movie VOBI search pointercorresponding to VOB of this cell, C_EPI_Ns which describes the numberof pieces of cell entry point information, C_V_S_PTM which describes thepresentation start time of this cell using the RTR presentation timedescription format, and C_V_E_PTM which describes the presentation endtime of this cell using the RTR presentation time description format.

Note that C_V_S_PTM and C_V_E_PTM satisfy the following conditions.

(1) In case of a cell in original PGC

C_V_S_PTM must be set in the first four VOBUs of the corresponding VOB;and

C_V_S_PTM must be set in the last four VOBUs of the corresponding VOB.

(2) In case of a cell in user defined PGC

O_C_V_S_PTM≦C_V_S_PTM<C_V_E_PTM≦O_C_V_E_PTM must hold.

where O_C_V_S_PTM indicates the presentation start time of an originalcell corresponding to VOB referred to by this cell, and O_C_V_E_PTMindicates the presentation end time of an original cell corresponding toVOB referred to by this cell.

FIG. 33 shows the contents of the movie cell entry point information(M_C_EPI) shown in FIG. 31.

This M_C_EPI has two types (type 1 and type 2). M_C_EPI of type 1without any text information is composed of EP_TY and EP_PTM, andM_C_EPI of type 2 with text information is composed of EP_TY, EP_PTM,and PRM_TXTI. FIG. 33 shows M_C_EPI of type 2.

As shown in FIG. 33, M_C_EPI includes EP_TY that describes the type ofentry point, EP_PTM that describes the presentation time of the entrypoint using the RTR presentation time format, and PRM_TXTI thatdescribes primary text information and the like of the entry point.

Upon playback, the value EP_PTM and cell playback time are convertedinto file pointers that point to VOBU by the time map TMAP information(see FIG. 25), and are also converted into physical addresses by thefile system.

PRM_TXTI in M_C_EPI is constructed by a 128-byte field. The first 64bytes of that field are used to describe primary text using an ASCIIcharacter set. When ASCII text is less than 64 bytes, “00h” fills blankbytes. The latter 64 bytes of the 128-byte field are used to describeprimary text of another character set (e.g., shift JIS or ISO8859-15).Note that “another character set” is described in VMGI₁₃ MAT, and isshared by all the pieces of primary text information in the disc.

Note that a terminal control code that assumes a value ranging from“01h” to “1Fh” is never described in PRM_TXTI.

EP_TY in M_C_EPI is comprised of 1-byte data including a 2-bit typeidentification code. If this identification code is “00b”, it indicatesthat M_C_EPI is of type 1 (empty primary text data or no data); if thecode is “01b”, it indicates that M_C_EPI is of type 2 (primary textdata).

This EP_TY has a 6-bit reserved field in addition to the 2-bit typeidentification code that identifies type 1 or 2. Using some or all thebits of this reserved field, the contents of PRM_TXTI in M_C_EPI can befurther specified. (If all the six bits are used, a maximum of 64different specifications may be made. More than 6 bits may be assignedto this designation code to specify more types.)

The bits using this reserved field will be referred to as a designationcode for designating the contents of the primary text informationhereinafter.

Specific bits in the designation code can designate whether PRM_TXTI inM_C_EPI shown in FIG. 33 is “text information” with “information type”and/or “information date” or “text information” without “informationtype” and/or “information date”.

Furthermore, specific bits in the designation code can designate whetherPRM_TXTI in M_C_EPI shown in FIG. 33 is “text information” withcorresponding “thumbnail information” in addition to “information type”and/or “information date”, or “text information” without “thumbnailinformation”. (The “thumbnail information” corresponds to, e.g.,thumbnail pointer information THM_PTRI shown in FIG. 29.)

Moreover, specific bits in the designation code can designate whetherPRM_TXTI in M_C_EPI shown in FIG. 33 consists of “thumbnail information”alone without any “text information” or “thumbnail information” with“text information”.

When the designation code (not shown) in EP_TY designates “informationtype”, “information date”, and “text information” shown in FIG. 33,these pieces of information can be used to express the followingcontents.

More specifically, “information type” describes an attribute of theentry point, “information date” describes the date of registration(recorded on the disc) of the entry point, and “text information”describes additional information (a brief comment of a picture at theentry point) that pertains to the entry point.

The attributes of the entry point described in “information type”include:

information type [1]=0, user mark (the user registers the entry point)

information type [1]=1; set mark (an apparatus such as a DVD_RTR videorecorder or the like registers the entry point)

information type [1]=3; erasion prohibition mark (corresponding to theerasion level flag described in the cell type in C_PBI shown in FIG. 12)

information type [1]=4; trash box mark (corresponding to information oftrash PGC shown in FIG. 16)

information type [1]=5 to 7; other marks Note that [1] in informationtype [1] means the first data field of the information type. If thisdata field has a 3-bit configuration, information type [1] can expresseight different marks.

FIG. 34 shows an example of the arrangement of an apparatus (RTR videorecorder) for recording (recording/playing back) digital moving pictureinformation (video program or the like) at variable recording rate usingoptical disc (DVD-RAM, DVD-RW, or DVD-R disc) 10 shown in FIG. 1.

The apparatus main body of the RTR video recorder shown in FIG. 34 hasdisc drive 32 for rotating a recording disc and reading/writinginformation on the disc, encoder 50 which constructs the recording side,decoder 60 which constructs the playback side, and microcomputer (MPU)30 for controlling operations of the overall apparatus.

Encoder 50 comprises analog-to-digital converter (ADC) 51, selector 52,video encoder 53, audio encoder 54, sub-picture encoder 55, formatter56, and buffer memory 57.

ADC 51 receives an external analog video signal+external analog audiosignal from AV input 42, or analog TV signal+analog audio signal from TVtuner 44. This ADC 51 converts the input analog video signal intodigital data at, e.g., a sampling frequency=13.5 MHz and the number ofquantization bits=8. (More specifically, luminance component Y, colordifference component Cr (or Y−R), and color difference component Cb (orY−B) are respectively quantized by 8 bits.)

Likewise, ADC 51 converts the input analog audio signal into digitaldata at, e.g., a sampling frequency=48 kHz and the number ofquantization bits=16.

When an analog video signal and digital audio signal are input to ADC51, the digital audio signal passes through ADC 51.

When a digital video signal and digital audio signal are input to ADC51, these signals pass through ADC 51.

A digital video signal output from ADC 51 is supplied to formatter 56via selector 52 and video encoder 53. Also, a digital audio signaloutput from ADC 51 is supplied to formatter 56 via audio encoder 54.

Selector 52 selects a signal output from video mixer 200 and sends it tovideo encoder 53 when a reduced-scale image (thumbnail picture) forediting (to be described later) is to be recorded.

Video encoder 53 has a function of converting the input digital videosignal into a digital signal compressed at variable bit rate on thebasis of the MPEG2 or MPEG1 specifications.

Audio encoder 54 has a function of converting the input digital audiosignal into a digital signal (or linear PCM digital signal) compressedat fixed bit rate on the basis of the MPEG or AC-3 specifications.

When a digital video signal (for example, a signal from a DVD videoplayer with an independent output terminal of a sub-picture signal) withthe structure shown in FIGS. 2 to 5 or FIGS. 17 and 18 is input from AVinput 42, or when a DVD video signal with such data structure isbroadcasted and is received by TV tuner 44, a teletext signal (closedcaption) component in the DVD video signal is input to sub-pictureencoder 55. Sub-picture data input to sub-picture encoder 55 is arrangedinto a predetermined signal format, and is then sent to formatter 56.

Formatter 56 executes predetermined signal processing of the input videosignal, audio signal, sub-picture signal, and the like using buffermemory 57 as a work area, and outputs recording data that matches theaforementioned format (file structure) to data processor 36.

In this processing, a cell is set as a minimum unit of main picture data(video data), and cell playback information C_PBI shown in FIG. 11 (orcell information CI shown in FIG. 27) is created. Then, theconfiguration of cells that construct program chain PGC, attributes ofmain picture, sub-picture, and audio data, and the like are set (some ofthese pieces of attribute information use information obtained uponencoding the respective data), and information management tableinformation (VMGI, VTSI shown in FIG. 3; or RTR_VMG shown in FIG. 20)including various kinds of information is created.

Encoded main picture data, audio data, and sub-picture data aresegmented into packs each having a predetermined size (2,048 bytes).Dummy packs are inserted into these packs, as needed. Note that timestamps such as PTS (presentation time stamp), DTS (decode time stamp),and the like are described in packs other than dummy packs, as needed.As for PTS of sub-picture data, a time arbitrarily delayed from PTS ofmain picture data or audio data in the identical playback time band canbe described.

Data cells are arranged in units of VOBUs to allow playback in the timecode order of data, thus forming VOB consisting of a plurality of cells.VOBS that combines one or more VOBs is formatted into a file structurethat matches VTS shown in FIG. 3 or RTR_MOV.VRO shown in FIG. 20.

The RTR video recorder shown in FIG. 34 comprises disc drive 32,temporary buffer memory 34, data processor (D-PRO unit) 36, and systemtime clock (STC) 38 as means for reading/writing (recording and/orplaying back) information with respect a recordable DVD_RTR disc.

Temporary buffer memory 34 is used to buffer a given amount of data tobe written on the disc (data output from encoder 50) via D-PRO unit 36,and to buffer a given amount of data played back from the disc (datainput to decoder 60) via D-PRO unit 36.

For example, when temporary buffer memory 34 comprises a 4-Mbytesemiconductor memory (DRAM), it can buffer recording or playback datafor approximately 8 seconds at an average recording rate of 4 Mbps. Whentemporary buffer memory 34 comprises a 16-Mbyte EEPROM (flash memory),it can buffer recording or playback data for approximately 30 seconds atan average recording rate of 4 Mbps. Furthermore, when temporary buffermemory 34 comprises a 100-Mbyte, very small HDD (hard disc drive), itcan buffer recording or playback data for 3 minutes or more at anaverage recording rate of 4 Mbps. Also, temporary buffer memory 34 canalso be used to temporarily store recording information when the disc isused up during recording, until that disc is exchanged by a new disc.

D-PRO unit 36 supplies DVD recording data from encoder 50 to disc drive32, receives a DVD playback signal played back from the disc from drive32, rewrites management information (directory record, VMGI_MAT,VTSI_MAT, RTR_VMG, and the like) recorded on the disc, and erases data(some or all fields of VTS, RTR_MOV.VRO, or the like) recorded on thedisc, under the control of MPU 30.

MPU 30 includes a ROM written with various control programs and thelike, a RAM which provides a word area required for executing programs,and the like, in addition to a CPU core of the microcomputer.

This MPU 30 executes processes such as free space detection of the discwhich is being used in recording, recording space (the number ofrecorded packs) detection, remaining space detection, warning, recordingmode change instruction, and the like, in accordance with the controlprograms stored in its ROM.

Furthermore, MPU 30 has a function of designating an erasion levelappending range to cell units (or entry point units), a function ofsetting an erasion level, a function of dividing a cell, a function ofdetecting the erasion level, and the like. With these functions, useroperability of the RTR video recorder system can be improved.

Of the execution results of various control programs by MPU 30, thecontents the user of the DVD_RTR video recorder should know aredisplayed on display panel 48 of the DVD_RTR video recorder, or aredisplayed on a monitor display as on-screen display (OSD).

Decoder 60 comprises separator 62 for separating the respective packsfrom DVD_RTR playback data with the aforementioned pack structure,memory 63 used upon executing pack separation and other signalprocesses, video decoder 64 for decoding contents of video packsseparated by separator 62, sub-picture decoder 65 for decoding thecontents of sub-picture packs separated by separator 62, audio decoder68 for decoding the contents of audio packs separated by separator 62,and video processor 66 for appropriately mixing sub-picture data fromsub-picture decoder 65 with video data output from video decoder 64,i.e., superposing sub-picture data such as menus, highlight buttons,superimposed dialogs, and the like on main picture data, and outputtingthem.

Note that video decoder 64 incorporates a thumbnail picture generatorfor generating an image (thumbnail picture) obtained by extracting andreducing a predetermined I-picture portion from, e.g., MPEG video datain accordance with a command from MPU 30.

This thumbnail picture is output to an external TV monitor via videomixer 0200 and DAC (digital-to-analog converter) 67, or is supplied tovideo encoder 63 via video mixer 200 and selector 52.

The thumbnail picture data supplied to video encoder 53 can be writtenin a predetermined dummy pack (see FIGS. 18 and 19) by formatter 56.

The output from video processor 66 is supplied to video mixer 200. Framememory 201 used for mixing video data is connected to video mixer 200.

A digital signal output from video processor 66 via video mixer 200 issupplied to an external monitor (not shown) such as a televisionreceiver via video DAC 67.

Or the digital signal from video processor 66 may be supplied to abuilt-in liquid crystal display (not shown) or the like of theapparatus.

The output from audio decoder 68 is supplied to an external device viaaudio DAC 69.

The digital video output from video mixer 200 or digital audio outputfrom audio DAC 68 may be externally output via an appropriate digitaloutput interface, although pertinent connections are not shown in thedrawings.

Furthermore, key input unit 49, and display panel 48 for displaying theoperation state and the like of the DVD-RTR recorder are connected toMPU 30.

FIG. 35 is a flow chart for explaining image recording by the apparatusshown in FIG. 34.

Upon receiving an image recording command from key input unit 49 (or apreserved recording program or key operation at a remote controller (notshown)), MPU 30 shown in FIG. 34 reads management data from disc 10 viadisc drive 32 (step A2), and determines a write area (step A4).

MPU 30 then sets management data (creates VMGI and VTSI files shown inFIG. 3; or creates RTR_VMG file shown in FIG. 20) in a management areato be able to write data in the determined area, and sets the writestart address of video data in disc drive 32 to prepare for datarecording (step A5).

If there is no recordable space (NO in step A3), a warning tone ormessage is generated or displayed.

MPU 30 then resets the time in STC 38. Note that STC 38 is a systemtimer, and recording or playback is done with reference to themeasurement value of this STC.

Furthermore, MPU 30 makes other setups (steps A6 and A7).

The flow of a video signal upon recording is as follows.

AV signals input from TV tuner 44 shown in FIG. 34 or an external deviceare A/D-converted, a video signal is supplied to video encoder 53, andan audio signal is supplied to audio encoder 54. Also, a teletext signalor the like is supplied from TV tuner 44 to SP encoder 55.

The respective encoders (53 to 55 in FIG. 34) compress and packetize theinput signals (note that each packet is formed to have a size of 2,048bytes per pack), and input the packets to formatter 56. The respectiveencoders determine PTS and DTS of each packet in accordance with thevalue of STC 38, as needed.

Formatter 56 temporarily stores packet data in buffer memory 57, thenpacks the input packet data, and mixes them in units of GOPs. Formatter56 appends a navigation pack to the head of each GOP, as needed, andinputs packs to D-PRO unit 36.

D-PRO unit 36 forms ECC groups in units of 16 packs, appends ECC data tothese groups, and sends them to disc drive 32. When disc drive 32 is notready to record on the disc, D-PRO unit 36 temporarily transfers ECCgroup data to temporary buffer memory 34, and waits until disc drive 32is ready to record. When disc drive 32 is ready to record, recording isstarted. In this case, a large-size memory is assumed as temporarybuffer memory 34 so as to store recording data for several minutes ormore by high-speed access.

At the end of recording, MPU 30 records address data of navigation packs(or navigation data) in fast-forwarding or rewinding data fields of therespective navigation packs (or navigation data), and records requiredinformation on the management area after recording, thus endingrecording (steps A8 to A14).

Note that MPU 30 shown in FIG. 34 can read out various kinds ofinformation from the file management area and the like on disc 10 shownin FIG. 1, and can write various kinds of information on the recordingarea of this disc by sending commands to D-PRO unit 36 via data bus.

At the end of recording, erasion level flags set in units of cells,which are used by the RTR video recorder system are cleared to permitplayback (step A13). That is, playback of all cells is permitted uponinitial recording.

This erasion level flag is described in C_PBI (FIG. 12). When an archiveflag (erasion prohibition flag) is stored in VMG, it is also cleared.

If M_C_EPI (FIG. 33) in RTR_VMG includes the erasion level flag or trashPGC information, it is also cleared.

The data processing upon playback is as follows.

Upon receiving a playback command, MPU 30 reads data on the managementarea via disc drive 32 and D-PRO unit 36, and determines the playbackaddress. MPU 30 then sends the determined playback data address and aread command to disc drive 32.

In response to the received command, disc drive 32 reads out sector datafrom the disc, performs error correction using D-PRO unit 36, andoutputs the readout data to decoder 60 in the form of pack data.

In decoder 60, separator 62 receives and packetizes the readout packdata. Depending on data contents, MPU 30 transfers video packet data(MPEG video data) to video decoder 64, audio packet data to audiodecoder 68, and sub-picture packet data to SP decoder 65, and saves thecontents of navigation packs (or navigation data) in its internal memoryto use them when required. In this manner, MPU 30 can quickly accessnavigation data anytime.

At the beginning of transfer of the respective packet data, PTS includedin a header is loaded to STC 38 (MPU 30 sets PTS in a navigation pack inSTC, or video decoder 64 automatically sets PTS of video data in STC38). After that, the respective decoders play back data in synchronismwith PTS values in packet data, and moving picture data with audio andsuperimposed dialog data can be played back on a TV monitor.

In some cases, an erasion level flag is described in cell playbackinformation (CPB_I), as shown in FIG. 12. Hence, before cell playback,the erasion level is checked, and if the cell is temporarily erased(i.e., level=01h), the control skips playback of that cell and startsprocesses of the next cell.

When a temporary erase flag is described in VOB information (VOB_GI),the VOB information of VOB entered in cell information is read outbefore reproducing (playback) the cell. Then, the status of the temoraryerase flag is checked. If the status indicates a temporarily-eased state(or the flag=01h), the playback of that cell is skipped, and the processof playing back the subsequent cell is activated.

That is, in this system, since erasion level flags are set in units ofcells, erasion setting (to automatically exclude a given cell from thoseto be played back) can be done in units of cells, thus allowing moreflexible presentation and management.

Accordingly, a temporary erasion process is done as follows.

FIGS. 36 and 37 are flow charts for explaining erasion level setting(temporary erasion process). FIG. 38 shows examples of windows displayedin this temporary erasion process, and FIG. 39 is a view for explainingthe principle of cell division upon executing the temporary erasionprocess.

When an erasion key of key input unit 49 shown in FIG. 34 (or a remotecontroller (not shown)) has been pressed, MPU 30 shown in FIG. 34 startsthe process shown in FIGS. 36 and 37.

1) It is checked if there is PGC with the trash PGC flag=01h in PGC_GIshown in FIG. 15, i.e., trash PGC (step B2). If no trash PGC is found, afile of trash PGC is prepared (step B3).

2) The user selects a title (VTS or PGC) (step B4).

3) A time bar corresponding to the playback time of the selected title(VTS or PGC), and a cursor for designating that time range (see the timebar in 15-min increments shown in FIG. 38) are displayed (step B5).

In this time bar display, PGC of interest may be divided in units ofcells using the dotted lines and the like, so as to inform the user thatthe range bounded by the dotted lines corresponds to an identical scene(one PGC). For example, in image sensing using a video camera, the rangefrom the beginning of recording to a pause or the end of recordingcorresponds to this scene. In a TV drama, the range from a given CM tothe next CM corresponds to this scene.

4) The user designates the erasion start position using a cursor key andmarker key of key input unit 49 (step B6), and the VOBU addresscorresponding to the designated position, and the like are saved in theinternal work memory (not shown) of MPU 30 (step B7).

At this time, when the start I-picture of VOBU pointed by the cursor issimultaneously displayed on the cursor window as a reduced-scale image(thumbnail picture), the user can recognize the contents of a cell atthe cursor position, thus allowing easy operation.

The playback time at the cursor position at that time can also bedisplayed. The playback time can be calculated by C_PBTM+C_ELTM withinthe range from the first cell to the immediately preceding cell of thetitle with reference to cell elapse time C_ELTM (FIG. 7) in a navigationpack and cell playback time C_PBTM (FIG. 12) in cell playbackinformation.

Or the playback time at the cursor position can be calculated withreference to the contents of time map information TMAPI (FIG. 25) andmovie cell general information M_C_GI (FIG. 32).

5) The user designates the erasion end position using the cursor key andmarker key of key input unit 49 (step B8), and the VOBU addresscorresponding to the designated position and the like are saved in thework memory (step B9).

6) Looking at the display in FIG. 38, the user confirms if he or sheagrees with the current selected range (the displayed range from erasionstart to erasion end) (step B10). If the user disagrees with that range(NG in step B10), the work memory is cleared to repeat the processes insteps B6 to B9.

7) If the user agrees with the displayed selected range (OK in stepB10), it is checked if cell division is necessary at the set startposition, i.e., if the cell start position matches the set startposition (step B11).

If no cell division is necessary at the start position (NO in step B11),the flow advances to step B16 in FIG. 37.

8) If cell division is necessary at the start position (YES in stepB11), the cell to be divided (CELL_N) is determined based on start andend VOBUs in C_PBI of each cell (step B12). Alternatively, the cellnumber which was determined and saved upon setting by the cursor is usedas CELL_N. Cell division is done using this CELL_N.

More specifically, start address C_LVOBU_SA, end address C_LVOBU_EA, andcell playback time C_PBTM of last VOBU in C_PBI of CELL_N are saved inthe work memory, and C_LVOBU_SA, C_LVOBU_EA, and C_PBTM are rewritten onthe basis of search information of a navigation pack of VOBU to bedivided (step B13).

Then, C_PBI next to CELL_N is moved by one cell (step B14).

Note that the processes in step B13 and B14 can also be done using timemap information TMAPI shown in FIG. 25 and PGC information PGCI shown inFIG. 27.

At the place reached in step B14, new cell playback information C_PBIwith the following contents is recorded (step B15 in FIG. 37).

That is, the same cell category C_CAT as that of CELL_N, playback timeC_PBTM of the divided cell, start address C_FVOBU_SA of first VOBU inthe divided cell, end address C_FILVU_EA of first ILVU in the dividedcell, start address C_LVOBU_SA of last VOBU in the divided cell, and endaddress C_LVOBU_EA of last VOBU in the divided cell are recorded as newcell playback information C_PBI of the divided cell.

9) Subsequently, the erasion level flag of the setting start cell (e.g.,cell 3 in the lower cell array in FIG. 39) is set in a playbackprohibition (temporary erasion) state.

The same processes as those in steps B11 to B15 are repeated for a cellat the setting end position (steps B16 to B20).

10) That is, it is checked if cell division is necessary at the settingend position (i.e., to check if the cell end position matches thesetting end position). If no division is necessary (NO in step B16), theflow advances to step B21.

11) If the end cell must be divided (YES in step B16), the cell to bedivided (CELL_M) is determined (that cell is determined based on startand end VOBUs in C_PBI of each cell. Or the cell number which wasdetermined and saved upon setting by the cursor is used). The determinedcell is divided (step B17).

More specifically, C_FVOBU_SA to C_LVOBU_EA, and C_PBTM in cell playbackinformation C_PBI of CELL_M are saved, and the saved C_FVOBU_SA toC_LVOBU_EA, and C_PBTM are rewritten based on search information of VOBUto be divided (step B18).

Then, C_PBI next to CELL_M is moved by one cell (step B19).

At the place reached in step B19, new cell playback information with thefollowing contents is recorded (step B20).

That is, the same cell category C_CAT as that of CELL_M, playback timeC_PBTM of the divided cell, start address C_FVOBU_SA of first VOBU inthe divided cell, end address C_FILVU_EA of first ILVU in the dividedcell, start address C_LVOBU_SA of last VOBU in the divided cell, and endaddress C_LVOBU_EA of last VOBU in the divided cell are recorded as newcell playback information C_PBI of the divided cell.

12) The erasion level flag of each cell before the setting end cell(e.g., cell 4 in the lower cell array in FIG. 39) is set in a playbackprohibition (temporary erasion) state (step B21).

13) C_PBI of each temporary erased cell (e.g., cells 3 and 4 in thelower cell array in FIG. 39) is added to trash PGC, and original PGCnumber PGC_N and original cell number C_ID_N are recorded in this C_PBI(FIG. 16) (step B22).

14) If cells to be subjected to erasion level setting (temporary erasionprocess) still remain (NO in step B23), operation repeats itself fromstep B6 in FIG. 36.

Upon completion of erasion level setting (temporary erasion process)(YES in step B23), pertinent data are written in trash PGC generalinformation (FIG. 15) to record data required for file management (stepB24).

Note that the processes for dividing a cell in steps B11 to B24 can alsobe done using information shown in FIGS. 21 to 33. More specifically,movie cell M_C_GI (FIG. 32) and movie cell entry point informationM_C_EPI (FIG. 33) of M_CI of the divided cell can be rewritten on thebasis of time map information TMAPI (FIG. 25) that corresponds to celldivision.

In this case, data in a navigation pack is not necessary, and the celldivision position can be specified by entry point information M_C_EPI#1to M_C_EPI#n shown in FIG. 31. Also, erasion level (temporary erasion)setting information can be described in character information in M_C_EPIshown in FIG. 33.

FIG. 40 is a flow chart for explaining recovery (restoration) and actualerasion of a cell in which an erasion level flag is set in a temporaryerasion state. FIG. 41 shows examples of windows displayed uponrecovering (restoring) and actually erasing a cell in which an erasionlevel flag is set.

In this embodiment, a process for recovering from a temporary erasionstate (playback prohibition state) to a playback permitted state is donein units of cells. (Although not shown as a flow chart, a similarrecovery process can be done in units of entry points.)

1) The user clicks a trash box mark (icon) by key operation on theremote controller (not shown) (or by mouse operation (not shown)) whileobserving the upper left window in FIG. 41 (step C2).

2) If trash PGC has been selected upon clicking the trash icon, MPU 30shown in FIG. 34 reads information (FIGS. 15 and 16) of trash PGC fromdisc 10 (step C3).

3) Then, a time bar is displayed in accordance with the playback time oftrash PGC, as illustrated on the upper central window in FIG. 41 (stepC4). At this time, title text “contents of trash box” is also displayedto indicate trash PGC. Furthermore, a cursor for designating a cell tobe recovered to a playback permitted state, and a reduced-scale image(thumbnail picture) of I-picture of that cell are displayed (step C5).

4) The user then designates a cell to be recovered to the playbackpermitted state (i.e., to cancel the temporary erasion state) using acursor key and marker key (not shown) on the remote controller (stepC6).

If the aforementioned erasion cancel designation is erroneously done orcells to be erasion-canceled still remain (NG in step C7), processes insteps C4 to C6 are repeated.

5) After the designated cell is confirmed (OK in step C7), the userdetermines if the designated cell is to be recovered to the playbackpermitted state or to be actually erased (step C8).

6) When the designated cell (or VOB) is to be recovered to the playbackpermitted state, MPU 30 specifies an original cell (or VOB) of theselected cell (or VOB) by referring to PGC_N and C_ID_N (or CI) of trashPGC shown in FIG. 16. MPU 30 then clears the erasion level flag (FIG.12) of that original cell (or VOB) to 00h (playback permitted), anddeletes information (PGC_N and C_ID_N; or CI) of the cell (or VOB) inthe temporary erasion state from trash PGC (step C9).

7) As to cell, when the designated cell is to be actually erased, MPU 30specifies an original cell of the selected cell by referring to PGC_Nand C_ID_N of trash PGC shown in FIG. 16. MPU 30 erases that originalcell, and deletes information (PGC_N and C_ID_N in FIG. 16) of theerased cell from trash PGC (step C10).

7*) As to VOB, when the designated VOB is to be actually erased, MPU 30erases the target cell information CI and shifts upward the subsequentCI to remove the space of erased CI where PGC_GI and PGI are updated(step C10).

At this time, the start and end file pointers (FPs) at the VRO file aredetected according to the VOB information (VOBI) (step C10).

The target VOBI is then erased, and the space of the erased VOBI isremoved where the movie AV file general information (M_AVFI_GI) andmovie VOBI search pointer (M_VOBI_SRP) are updated (step C10).

Thereafter, the target video data is erased from the VRO file, tothereby release from the file system the data between the start and endfile pointers (step C10).

FIG. 42 is a flow chart showing automatic erasion (disc arrangingprocess) of a cell in which an erasion level flag is set. FIG. 43 showsexamples of windows displayed upon erasing a cell in which an erasionlevel flag is set.

The disc arranging process shown in FIG. 42 is executed when the timerreservation time before the beginning of recording is longer than thetime corresponding to the remaining space of disc 10, when the remainingspace of disc 10 becomes short during recording, or when the useractually wants to erase a cell in a temporary erasion state in trashPGC.

More specifically, when the remaining space of disc 10 becomes short orwhen the user inputs an erasion command, MPU 30 executes the discarranging process shown in FIG. 42.

1) If the control enters this process, message “disc arranging will bedone” is displayed on the TV monitor screen, as illustrated on the upperleft window in FIG. 43 (step D2).

2) MPU 30 then instructs disc drive 32 to start disc arranging (stepD3).

In response to this instruction, the internal MPU (not shown) of discdrive 32 executes the following process of the disc arranging mode (stepD10).

More specifically, the internal MPU checks based on the contents of thetrash PGC flag shown in FIG. 15 if trash PGC is present on currently setdisc 10 (step D11).

If trash PGC with a trash PGC flag=01h is found, the internal MPU readsout information (FIGS. 15 and 16) of that PGC from disc 10 (or a buffermemory if it is recorded on the buffer memory of temporary buffer memory34) (step D12).

The internal MPU erases all original cells in a temporary erasion state(i.e., those with an erasion level flag (FIG. 12)=01h) in trash PGC onthe basis of the readout information (PGC_N and C_ID_N in FIG. 16), andalso erases empty trash PGC (step D13).

The internal MPU then sends back to MPU 30 status indicating that erasedcells exist (steps D14 and D15).

On the other hand, if no trash PGC is found on that disc (NO in stepD11), the internal MPU sends back to MPU 30 status indicating that acell to be erased does not exist (steps D17 and D15).

3) While disc drive 32 is executing the processes in steps D11 to D17,message “disc arranging is now performed” illustrated on the upper rightwindow in FIG. 43 is displayed on the TV monitor screen (step D4).

4) If disc drive 32 has completed the processes in steps D11 to D17 andsends back status (YES in step. D5), MPU 30 checks if erased cellsexist.

5) If erased cells exist (YES in step D6), since the remaining space ofdisc 10 increases accordingly, the remaining recordable time isrecalculated (step D7).

This recalculation can be made on the basis of the number of sectors ofthe unrecorded space of disc 10, the mode (MPEG1 or MPEG2) used in thesubsequent recording, the average recording rate (bits/sec) used in thesubsequent recording, contents (%) of dummy packs, and the like.

If no erased cell exists (NO in step D6), since the remaining space ofdisc 10 remains the same even after disc arranging, the flow skips therecalculation of the remaining recordable time.

6) After the remaining time of disc 10 is obtained, as described above,message “disc arranging completed successfully. Remaining recordabletime will be 6 min 15 sec with average rate of 4 Mbps”, as shown at thecenter in FIG. 43, is displayed on the TV monitor screen (step D8).

With this process, the recorded files on the disc in use are arranged,and temporary erased cells are actually erased, thus increasing therecordable space of the arranged disc.

Also, the erasion level can be set in small units.

FIG. 44 is a flow chart for explaining playback upon playing back thecontents on the disc that describes the aforementioned erasion levelinformation.

Upon receiving a playback start command, it is checked if the disc is aDVD_RTR disc (step E2).

If the disc is a DVD_RTR disc, management information VMGI is read (stepE3), and menus and the like are displayed, as needed.

If a title set to be reproduced or played back (or a title to be playedback) has been selected (step E4), VTSI (or RTR_VMG) of that title isread (step E5) to set up an environment, and PGC information (PGCI) orVOB information (VOBI) is stored.

The title (or program) is selected and determined (step E6), and aprogram number, cell number, and the like to be played back aredetermined to determine the playback order and the like (step E7).

The video decoder, sub-picture decoder, audio decoder, and the like areinitially set up (step E8).

Subsequently, a preprocess command is executed (step E9), and it ischecked if the read cell is a temporary erased cell (step E10).

Incidentally, no preprocess command is executed in a RTR_DVD system.

If the read cell has no flag of the erasion state (i.e., it is not inthe temporary erasion state), cell playback is executed (step E11).

If the read cell describes a flag of the erasion state (temporaryerasion state), playback of that cell is skipped, and the next cell isplayed back.

After the last cell has been played back (YES in step E12), a stillpicture is played back for a preset period of time (a predeterminedperiod of time including zero time) (step E13), and a postprocesscommand is executed (step E14).

If the last cell has not been played back yet (NO in step E12), the cellnumber is incremented by one (step E18), and the processes in steps E10,E11, and E18 are repeated until the last cell is played back.

Upon completion of playback of the last cell and execution of thepostprocess command, if the user has pressed a stop button on the remotecontroller to quit playback (YES in step E15), a process for completingplayback is executed (step E16), and the apparatus (RTR video recorder)is at rest to wait for the next user command.

On the other hand, even after completion of playback of the last celland execution of the postprocess command, if the user has pressed a playbutton on the remote controller to direct playback start (NO in stepE15), the processes in steps E9 to E15 are executed again.

Incidentally, no postprocess command is executed in the RTR_DVD system.

FIGS. 45–48 are a set of flow charts explaining a manner of dividingvideo objects (VOB) and cells.

FIG. 49 explains a manner of dividing cells where one cell is equal toone VOB, and FIG. 50 explains a manner of dividing VOBs where one cellis not equal to one VOB.

As shown in FIG. 45, when a user depresses a key for setting the eraseprohibition, a control device (e.g., MPU 30 in FIG. 34) acts on decoder60, etc., so that the time bar and thumbnail picture(s) as shown in FIG.38 are displayed on the screen of a TV monitor (not shown) (step ST100).

The user may move the cursor displayed on the screen, using cursor keysof key input section 49 or a remote controller (not shown). When thecursor is moved, the content of displayed thumbnail picture is changedcorrespondingly. During the cursor key manipulation, the user can selecta picture in the PGC (step ST102). At this time, the selected pictureindicates the start portion of the erase prohibition.

Then, the displayed position of the selected picture moves downward, andthe running time of leading VOBU (video object unit) of the movedpicture is displayed on the screen. At this time, the start PTM(presentation time) of this VOBU is stored in a RAM or register (notshown) of MPU 30 (step ST104).

The user may further select a picture in the PGC (step ST106).

Then, the displayed position of the selected picture moves downward, andthe end PTM of selected VOBU is stored in the RAM or register (notshown) of MPU 30 (step ST108).

At this time, the user can confirm his/her selections of the displayedpictures (step ST110).

If the user is not satisfied (NG at step ST110), the process returns tostep ST0100.

When the user is satisfied (OK at step ST110), it is checked whether adivision of the start VOB is necessary (step ST112).

If the division of the start VOB is not necessary (NO at step ST112),the process goes to step ST122 described hereinafter.

When the division of the start VOB is necessary (YES at step ST112), theVOB (VOB#n) to be divided (which is located at the start portion) isdetermined (step ST114).

Then, start PTM of VOB#n (VOB_S_PTM), end PTM of VOB#n (VOB_E_PTM), andtime map information (TMAPI) are stored in the RAM or register of MPU 30(step ST116).

At this time, the end PTM of VOBU#m−1 which proceeds by one to the VOBUof the start PTM of the determined area is set at VOB_E_PTM (stepST116).

Further, a time entry (TM_ENT) and a VOBU entry (VOBU_ENT) of VOBU nextto VOBU#m−1 are deleted, and the number of each of TM_ENT and VOBU_ENTof time map general information (TMAP_GI) are updated or changed to thecorresponding number of each of TM_ENT and VOBU_ENT obtained after thedeletion (step ST116).

Then, video object information (VOBI) of VOB(s) next to VOB#n is movedby one VOB (step ST118).

A space is created by the deletion of step ST116. The new VOBI of stepST118 is recorded in the created space (step ST120), where VOB type(VOB_TY), VOB recording time (VOB_REC_TM), sub-second information ofVOB_REC_TM (VOB_REC_TM_SUB), and movie VOB stream information number(M_VOB_STIN) are the same as those of VOB#n. VOB_V_S_PTM represents thestart PTM of this VOB. VOB_V_E_PTM (end PTM of this VOB) represents theoriginal VOB_V_E_PTM of the divided VOB.

Further, data of a group from “the TM_ENT and VOBU_ENT of the dividedVOBU including the start PTM of the determined area” to “the TM_ENT andVOBU_ENT of the last VOBU” are set at TMAPI (step ST120).

Still further, each number of the TM_ENT and VOBU_ENT of a time mapgeneral information (TMAP_GI) is updated or changed to the correspondingnumber obtained by the above setting at the TMAPI (step ST120).

The reference will be made to FIG. 46.

It is checked whether a division of the end VOB is necessary (stepST122).

If the division of the end VOB is not necessary (NO at step ST122), theprocess goes to step ST132 described hereinafter.

When the division of the end VOB is necessary (YES at step ST122), theprocess goes to step ST124 described hereinafter.

When the division of the end VOB is necessary (YES at step ST122), theVOB (VOB#k) to be divided (which is located at the last portion) isdetermined (step ST124).

Then, start PTM of VOB#k (VOB_S_PTM), end PTM of VOB#k (VOB_E_PTM), andtime map information (TMAPI) thereof are stored in the RAM or registerof MPU 30 (step ST126).

At this time, the end PTM of the determined area is set at VOB_E_PTM(step ST126).

Further, the TM_ENT and the VOBU_ENT of VOBU next to VOBU of end PTM ofthe determined area are deleted, and the number of each of TM_ENT andVOBU_ENT of TMAP_GI are updated or changed to the corresponding numberof each of TM_ENT and VOBU_ENT obtained after the deletion (step ST126).

Then, video object information (VOBI) of VOB(s) next to VOB#k is movedby one VOB (step ST128).

A space is created by the deletion of step ST126. The new VOBI of stepST128 is recorded in the created space (step ST130), where VOB_TY,VOB_REC_TM, VOB_REC_TM_SUB, and M_VOB_STIN are the same as those ofVOB#k. VOB_V_S_PTM represents the start PTM of VOBU next to the PTM ofthe end of the determined area. VOB_V_E_PTM (end PTM of this VOB)represents the original VOB_V_E_PTM of the divided VOB.

Further, data of a group from “the TM_ENT and VOBU_ENT of the VOBU nextto the VOBU of the end PTM of the divided area” to “the TM_ENT andVOBU_ENT of the last VOBU” are set at TMAPI (step ST130).

Still further, each number of the TM_ENT and VOBU_ENT of TMAP_GI isupdated or changed to the corresponding number obtained by the abovesetting at the TMAPI (step ST130).

Then, within a movie AV file information general information(M_AVFI_GI), the number of search pointers (SRP_Ns) is increased by thenumber of VOBI caused by the division, and the value of search pointer(SRP) is updated or changed (step ST132).

Thus, the VOB number is updated or changed.

Thereafter, a flag of the temporary erase (TE) is set at VOBI (VOB_TY)of VOB in the determined area (step ST134).

The reference will be made to FIG. 47.

It is checked whether (any) VOB is divided (step ST136).

If no VOB is divided (NO at step ST136), the process goes to step ST158described hereinafter.

When any VOB is divided (YES at step ST136), it is further checkedwhether the divided VOB is the start VOB (step 138).

If the start VOB is not divided (NO at step ST138), the process goes tostep ST158.

When the start VOB is divided (YES at step ST138), it is still furtherchecked whether the divided point of the start VOB matches the boundaryof related cells (step 140).

When the divided point matches the boundary of cells (or the boundary ofVOBS) (YES at step ST140), no cell division (or VOB division) isnecessary. Then, only movie VOBI search pointer number M_VOBI_SRPN inmovie cell general information M_C_GI of cells after the divided pointis updated or changed accordingly (step ST142).

Then, the process goes to step ST158.

If the divided point does not match the boundary of cells (or theboundary of VOBS) (NO at step ST140; see the vertically directed arrowsin the illustration of FIG. 49 or 50), then the cell (called CELL-N) tobe divided, located at the start or leading portion of the dividingarea, is determined (step ST144).

The end PTM of CELL-N (C_V_E_PTM) is updated or changed to the end PTM(E_PTM) of the divided VOB (step ST146).

When any entry point (EP) exists after the updated E_PTM, the entrypoint information (EPI) of the EP is stored, the EP is deleted from thecurrent (or present) cell information (CI), and the number of EPI(EPI_Ns) is updated so that the EPI_Ns is reduced by the number ofdeleted EP (step ST146).

Then, cell information (CI) of cell(s) next to CELL-N is moved by one CI(step ST148).

A space is created by the deletion of step ST146. The new CI of stepST148 is recorded in the created space (step ST150), where cell type(C_TY) is the same as that of CELL-N, the movie VOBI search pointernumber (M_VOBI_SRPN) of M_C_GI of VOB created by division is updated orchanged, the start PTM of the cell (C_V_S_PTM) and end PTM of the cell(C_V_E_PTM) are updated or changed to the start PTM (S_PTM) and end PTM(E_PTM) of VOB created by division, respectively, stored entry pointinformation (EPI) is added, and the number of EPI (EPI_Ns) is updated orchanged to the added number of EPI (step ST150).

The reference will be made to FIG. 48.

If the end VOB is not divided (NO at step ST158), the process goes tostep ST172.

When the end VOB is divided (YES at step ST158), it is checked whetherthe divided point of the end VOB matches the boundary of related cells(step 160).

When the divided point matches the boundary of cells (or the boundary ofVOBS) (YES at step ST160), no cell division (or VOB division) isnecessary. Then, only movie VOBI search pointer number M_VOBI_SRPN inmovie cell general information M_C_GI of cells after the divided pointis updated or changed accordingly (step ST162).

Then, the process goes to step ST172.

If the divided point does not match the boundary of cells (or theboundary of VOBS) (NO at step ST160), then the cell (called CELL-M) tobe divided, located at the end or trailing portion of the dividing area,is determined (step ST164).

The end PTM of CELL-M (C_V_E_PTM) is updated or changed to the end PTM(E_PTM) of the divided VOB (step ST166).

When any entry point (EP) exists after the updated E_PTM, the entrypoint information (EPI) of the EP is stored, the EP is deleted from thecurrent (or present) cell information (CI), and the number of EPI(EPI_Ns) is updated so that the EPI_Ns is reduced by the number ofdeleted EP (step ST166).

Then, cell information (CI) of cell(s) next to CELL-M is moved by one CI(step ST168).

A space is created by the deletion of step ST166. The new CI of stepST168 is recorded in the created space (step ST170), where cell type(C_TY) is the same as that of CELL-M, the movie VOBI search pointernumber (M_VOBI_SRPN) of M_C_GI of VOB created by division is updated orchanged, the start PTM of the cell (C_V_S_PTM) and end PTM of the cell(C_V_E_PTM) are updated or changed to the start PTM (S_PTM) and end PTM(E_PTM) of VOB created by division, respectively, stored entry pointinformation (EPI) is added, and the number of EPI (EPI_Ns) is updated orchanged to the added number of EPI (step ST170).

Then, each M_VOBI SRPN in M_C_GI of cells other than the divided pointis updated or changed (step ST172).

At this time, information pieces, such as the total number of cells(CI_SRP_Ns) in PGC general information (PGC_GI), the number of cells(C_Ns) in program information (PGI), the cell information search pointer(CI_SRP), etc., are also updated or changed (step ST172).

Further, when user defined PGC information (UD_PGCI) exists, similarprocessing will be made with respect to UD_PGCI (step ST172).

Finally, the user may confirm whether or not the setting of temporaryerasion is completed (step ST174).

If the temporary erasion is not completed (NO at step ST174), theprocess returns to step ST100 of FIG. 45.

When the user depresses an end key or the like, the condition ofcompleting the temporary erasion setting is entered (YES at step ST174),and the operation of FIGS. 45–48 is finished.

The present invention is not limited to the aforementioned embodiment.Software that includes the processing sequences shown in the respectiveflow charts is recorded in advance on a recording medium (disc 10 shownin FIG. 1 or the like), and is read by a playback apparatus (or apersonal computer with a DVD-RAM drive) to automatically set up anenvironment for implementing the processes of the respective flowcharts.

In other words, the present invention includes a case wherein the mediumitself has information (software application) for implementing theprocesses of the respective flow charts.

The characteristic features of the above-mentioned embodiment can besummarized as follows.

A recording medium is constructed by a management area and data area,which divisionally records data in one or more sequences (programchains). Each sequence consists of one or more cells, and one cellconsists of one or more data units. Each data unit is recorded bypacking video and audio data to be played back within a predeterminedperiod of time in a plurality of packs. The management area(hierarchically) contains a management table for managing the sequences,a management table for managing the cells, and a management table formanaging the data units.

Note that one feature is that temporary erasion playback sequenceinformation (PGCI of trash PGC) is recorded in the management area.Another feature is that the temporary erasion playback sequenceinformation records an original PGC number and cell number of atemporary erased cell.

A recording/playback method and apparatus are characterized by having acell erasion level setting means for appending erasion level informationto the cell management table. Also, the method and apparatus arecharacterized by having a cell division detection unit (a function of.MPU 30) for, when temporary erasion is designated in units of dataunits, checking if the designated data unit is present at a division ofa cell, a cell division unit (another function of MPU 30) for dividing acell when the cell is divided based on a signal from the detection unit,and an erasion level setting unit (still another function of MPU 30) forappending erasion level data to a cell corresponding to the designateddata unit.

The playback method and apparatus are further characterized by having anerasion level range designation unit (still another function of MPU 30)for displaying time information corresponding to the playback time of asequence, and designating an erasion level range using the timeinformation, and a video display unit (still another function of MPU 30)for displaying video data of a data unit closest to a display timecorresponding to the designated time position, so as to allow the userto easily set (or cancel) the erasion level.

Furthermore, the method and apparatus are characterized by having anerasion level designation unit (still another function of MPU 30) fordisplaying time information corresponding to the playback time of asequence, and designating an erasion prohibition range using the timeinformation, and a video display unit (still another function of MPU 30)for displaying the playback time corresponding to the designated timeposition, so as to allow the user to easily set (or cancel) the erasionlevel.

Moreover, the recording/playback method and apparatus are characterizedby having a cell designation unit (still another function of MPU 30) fordesignating a temporary erased area in units of cells, and a cellrecovery unit (still another function of MPU 30) for recovering a celldesignated by the designation unit.

Further, the method and apparatus are characterized by having a celldesignation unit (still another function of MPU 30) for designating atemporary erased area in units of cells, and a cell actual erasion unit(still another function of MPU 30) for actually erasing the celldesignated by the cell designation unit.

In addition, the method and apparatus for recording/playing backinformation on/from a recordable recording medium are characterized byhaving a cell arranging unit (still another function of MPU 30) forerasing a temporary erased cell when the remaining recordable spacebecomes smaller than a predetermined amount.

Also, the method and apparatus are characterized by having a PGCarranging unit (still another function of MPU 30) for erasing trash PGCafter the temporary erased cell has been erased.

The method and apparatus are also characterized by having a trash PGCIcreation unit (still another function of MPU 30) for creating sequenceinformation which can be played back as a sequence that can be playedback by joining temporary erased cells.

Furthermore, the method and apparatus are characterized by having arecording unit for recording sequence information from the trash PGCIcreation unit.

Moreover, the method and apparatus are characterized by having a trashPGCI display unit for displaying sequence information which can beplayed back as a sequence that can be played back by joining temporaryerased cells.

To restate, according to the present invention, the erasion level can bedesignated (or canceled) in small units, thereby allowing flexible datamanagement.

1. An information recording medium configured to have data recordedthereon and data reproduced therefrom by an informationrecording/reproducing apparatus, said data including audio/video dataand control information for managing said audio/video data, theinformation recording medium comprising: a data area configured to storesaid audio/video data included in one or more video objects; and amanagement area separate from said data area and configured to storesaid control information, wherein said control information includesmovie AV file information having movie video object informationcorresponding to one of said video objects, said movie AV fileinformation includes M₁₃ AVFI general information and one or more movieVOBI search pointers, said movie video object information includes movievideo object general information containing temporary erase informationof one of said video objects, one of said video objects is configured tobe set at a temporarily erased state, said temporarily erased stateindicated by said temporary erase information, a video objectcorresponding to said temporarily erased state results from a divisionof an original video object including said audio/video data, a startposition of said division is set as time information, said controlinformation includes program chain information having cell informationcorresponding to a cell, said cell information includes cell generalinformation and one or more pieces of cell entry point informationcorresponding to cell entry points of said cell, said cell generalinformation includes information of a type of said cell, movie VOBIsearch pointer numeral information corresponding to one of said videoobjects of said cell, information describing a number of said cell entrypoint information, information describing a presentation start time ofsaid cell, and information describing a presentation end time of saidcell, and one piece of said cell entry point information includes typeinformation of one of said cell entry points and information of apresentation time for one of said cell entry points.
 2. An apparatus forreproducing information from an information recording medium as definedin claim 1, said apparatus comprising: a first reproducer configured toreproduce said control information from the management area; and asecond reproducer configured to reproduce said audio/video data from thedata area.
 3. A method for recording information on an informationrecording medium, the information recording medium comprising, a dataarea configured to store said audio/video data included in one or morevideo objects; and a management area separate from said data area andconfigured to store said control information, wherein said controlinformation includes movie AV file information having movie video objectinformation corresponding to one of said video objects, said movie AVfile information includes M_AVFI general information and one or moremovie VOBI search pointers, said movie video object information includesmovie video object general information containing temporary eraseinformation of one of said video objects, one of said video objects isconfigured to be set at a temporarily erased state, said temporarilyerased state indicated by said temporary erase information, a videoobject corresponding to said temporarily erased state results from adivision of an original video object including said audio/video data, astart position of said division is set as time information, said controlinformation includes program chain information having cell informationcorresponding to a cell, said cell information includes cell generalinformation and one or more pieces of cell entry point informationcorresponding to cell entry points of said cell, said cell generalinformation includes information of a type of said cell, movie VOBIsearch pointer numeral information corresponding to one of said videoobjects of said cell, information describing a number of said cell entrypoint information, information describing a presentation start time ofsaid cell, and information describing a presentation end time of saidcell, and one piece of said cell entry point information includes typeinformation of one of said cell entry points and information of apresentation time for one of said cell entry points, said methodcomprising: recording said audio/video data on the data area; andrecording said control information on the management area.
 4. A methodfor reproducing information from an information recording medium, theinformation recording medium comprising, a data area configured to storesaid audio/video data included in one or more video objects; and amanagement area separate from said data area and configured to storesaid control information, wherein said control information includesmovie AV file information having movie video object informationcorresponding to one of said video objects, said movie AV fileinformation includes M_AVFI general information and one or more movieVOBI search pointers, said movie video object information includes movievideo object general information containing temporary erase informationof one of said video objects, one of said video objects is configured tobe set at a temporarily erased state, said temporarily erased stateindicated by said temporary erase information, a video objectcorresponding to said temporarily erased state results from a divisionof an original video object including said audio/video data, a startposition of said division is set as time information, said controlinformation includes program chain information having cell informationcorresponding to a cell, said cell information includes cell generalinformation and one or more pieces of cell entry point informationcorresponding to cell entry points of said cell, said cell generalinformation includes information of a type of said cell, movie VOBIsearch pointer numeral information corresponding to one of said videoobjects of said cell, information describing a number of said cell entrypoint information, information describing a presentation start time ofsaid cell, and information describing a presentation end time of saidcell, and one piece of said cell entry point information includes typeinformation of one of said cell entry points and information of apresentation time for one of said cell entry points, said methodcomprising: reproducing said control information from the managementarea; and reproducing said audio/video data from the data area.